Amateur golfers will line up on Thursday at the Trump National Doral near Miami, having agreed to pay more than $9,000 apiece to play a friendly round alongside some of the world’s top professionals.

Rooms at the resort hotel will fill up with fans as a pro tournament featuring some of the biggest names in the sport gets underway on Friday. The resort’s restaurants and bars will pull in more business, and the Trump name will be beamed around the world on television and the internet.

Behind this surge in business at one of former President Donald J. Trump’s properties is his deal to host tournaments for LIV Golf, the upstart league sponsored by Saudi Arabia’s sovereign wealth fund.

LIV’s eagerness to pay to have Mr. Trump host tournaments at his resorts is just one more example of the ties between the Saudis and the Trump family even as he seeks the presidency again, an arrangement that continues to generate conflicts of a type and scale unique to Mr. Trump.

Mr. Trump spoke recently with Saudi Arabia’s leader, Crown Prince Mohammed bin Salman, two people briefed on the discussion said; the Biden administration has been working with Saudi Arabia on a Middle East peace plan. It is not clear what Mr. Trump and the Saudi leader discussed. Officials representing Mr. Trump did not respond to requests for comment.

At the same time, the investment firm set up by Mr. Trump’s son-in-law, Jared Kushner, with $2 billion in funding from the same Saudi sovereign wealth fund that has bankrolled the LIV Golf league, has been accelerating its deal making in recent months in the United States and abroad.

The Trump family ties to the Saudi government have raised questions not just because of Mr. Trump’s quest to return to the White House but also because of their intersection with the evolving nature of Mr. Trump’s business, which was once closely associated with city-center hotels but is now increasingly focused on golf.

As of the end of last year, the Trump Organization had sold or lost branding deals with six hotels around the world, most recently the Trump Waikiki in Hawaii and the Trump International Hotel in Washington. The other hotels dropping the Trump name have been in Vancouver, Toronto, Panama and the SoHo neighborhood of New York City, collectively totaling 1,893 rooms.

This leaves the Trump family with only three city-center hotels, in New York, Chicago and Las Vegas.

The rest of its hospitality industry holdings worldwide, including the Doral in Florida, are almost entirely built around golf courses. In the last three years, they have seen their standing bolstered internationally as a result of the LIV Golf tournaments, funded lavishly by Saudi Arabia’s sovereign wealth fund to lure top stars like Jon Rahm, Phil Mickelson and Brooks Koepka.

In an interview, Eric Trump, one of the former president’s sons, said the shift in the company’s hospitality industry holdings reflected the rapid growth of the golf industry since the pandemic, a trend that is benefiting the family’s 11 domestic golf clubs and its four overseas.

“The leisure market has been the hottest market in the hotel world,” he said, referring in particular to golf resorts. “The golf clubs are full.”

But the slump in the city-center hotel business clearly was not something the Trump family had planned. A decade ago the family started a national marketing campaign to push what it was then calling “the Trump Hotel Collection,” a growing chain of boutique hotels in cities around North America and other parts of the world. It even started its own frequent visitor program it called the Trump Card.

“Ours is a lifestyle where you can do more, experience more and live life without boundaries, limits or compromise,” the company boasted in its marketing campaign, listing off many of the hotel properties that have now been stripped of the Trump name.

The Trump family, at the time, hired a well-known hotel industry executive, Eric Danziger, to help plot out a major expansion of the brand, predicting that it would eventually include dozens of hotels in locations worldwide. But Mr. Danziger has since left the company, after it effectively dropped its grand hotel expansion plans.

Documents prepared for the Trump family and its lenders offer their own explanation for the decline of the city-center hotel brand — pointing at Mr. Trump himself.

“According to management, the Trump brand has negatively impacted the subject’s performance,” said a 2021 appraisal of the Doral hotel prepared for Deutsche Bank, one of Mr. Trump’s lenders.

“Mr. Trump is a polarizing figure who ignites strong feelings from both supporters and supporters of his political opponents,” the appraisal added. “This resulted in many groups canceling events at the property.”

The appraisal, marked “highly confidential,” was made public late last year as part of the court proceedings in New York in which Mr. Trump was accused in a civil case by the state’s attorney general of inflating the value of some of his properties.

A second appraisal prepared in 2022 about the Doral — also made public recently through the New York lawsuit — concluded that if the Trump family sold the hotel, a new operator could expect to see occupancy and the daily average room rates jump almost immediately.

The problems extend to the Trump hotels in other locations.

Occupancy at the Trump International Hotel and Tower Chicago for a one-year period through September 2023 averaged just 49 percent, according to a market study prepared for the Trump Organization, 15 percentage points lower than its competitors in Chicago.

The Chicago hotel data, released to The New York Times in response to an open-records request by the local tax assessor, showed that the greatest weakness for the Trump hotel compared with its competitors was large group sales, another sign that corporations and other organizations avoid the Trump family’s hotel.

Further complicating the Trump hotel business plans is the long list of projects that were canceled or delayed, including Trump-branded hotels in Dubai, New Orleans and the Dominican Republic, and two in Indonesia. Plans to start two new hotel chains in the United States — they were to be called Scion and American Idea — were abandoned while Mr. Trump was in the White House.

One of the few new international resort projects that is moving ahead rapidly now is in Oman, which is backed by a Saudi Arabia-based real estate company.

The 14-year-old, 462-room Trump hotel in Hawaii left the Trump brand in November. Donald Trump Jr. was asked about the decision at the New York trial, with one lawyer for the state asking him if “this is a reflection that the hotel is abandoning the Trump brand to go with Hilton.” Mr. Trump responded: “That is what they are doing, I guess.”

By contrast, Trump golf courses in locations including Jupiter, Fla., Northern Virginia, West Palm Beach, Fla., and Charlotte, N.C., among other locations, saw major jumps in net profits in recent years, the court records show. Revenues from golf as well as food and beverage sales at the Doral in Miami also surged.

Initiation fees to join two of the Trump golf clubs in Florida have jumped to as much as $400,000, Eric Trump said, and annual dues are also now higher.

This jump in golf revenues at Bedminster and Doral coincides with the decision by LIV Golf, starting three years ago, to begin holding tournaments at Trump family venues. Attracting professional golf has long been a goal of the former president, who has otherwise largely been snubbed by major professional golf organizations such as the P.G.A. of America, which canceled a planned tournament at Bedminster after the 2021 assault on the Capitol.

Mr. Trump announced the news of this year’s Doral event himself, writing in a December post on Truth Social that “TRUMP NATIONAL DORAL, in Miami, has just signed with LIV GOLF to host a Championship Tournament in April, 2024.” The league played three tournaments at Trump courses last year, in Florida, New Jersey and Virginia — more than any other golf course brand worldwide.

Trump Organization executives said the direct payments from LIV Golf were relatively small, beyond covering the costs of hosting the tournaments and any related renovations to the golf courses and facilities. LIV Golf itself will be giving out $25 million in prizes to the 54 professional players.

“They want to use my properties because they’re the best properties,” Mr. Trump said at a LIV tournament at Trump National Golf Club Washington last May, calling the payments from LIV “peanuts for me.”

But the indirect revenues for the Trump family could be considerable. That is on display this week at Doral, where hotel occupancy is way up. Just a week ago during a visit by a reporter to the Doral, the 643-room hotel, its conference rooms and its restaurants were relatively quiet, even during the otherwise busy spring break time in Florida. Eric Trump said he expected tens of thousands of golf fans at the Doral resort through the weekend.

The asking price for hotel rooms at the Doral more than doubled as the tournament approached, reaching nearly $1,000 a night for a basic room.

Private chalets to watch the tournament are rented out for up to $89,000 for the three-day event, while a spot in the so-called Birdie Shack on the 16th green can be secured for $249, including three drinks and D.J.s playing music.

Akon, the Senegalese American singer, will also have a LIV-sponsored concert at the golf resort on Saturday, pulling in more crowds and spending at the resort. And the tournament will be broadcast on the CW network, bringing at least some additional brand attention to the club.

The Trump Organization and LIV Golf both declined to say what share of these revenues the Trump family gets or what other payments it receives. A LIV spokesman said only that the arrangement with the Trump family was “comparable terms with any other U.S. venue.”

Doug Mayer, thespokesman, also rejected any suggestion that LIV had picked the Trump family venues as some sort of a political favor by the Saudi government. He instead pointed to resistance elsewhere in the United States by professional golf to the league as one reason it had turned to the Trump family.

“LIV Golf is an independent business and commercial entity that is solely focused on the game of golf, the business of golf and increasing competition in the global marketplace,” he said in a statement. “The league’s mission has always been extremely clear — suggestions otherwise are not new and have been repeatedly proven meritless.”

The Trump family recently secured the right from local city officials to build as many as five high-rise buildings with a total of 1,410 condos and villas at the Trump Doral resort. The approval has already increased the resale value of the Doral holdings for the Trump family, even if the hotel itself has a relatively low occupancy. But there is no start date yet.

Eric Trump dismissed any suggestion that the Trump family, given the various legal challenges, might have a hard time getting a bank loan to build the project.

“When the market’s right and we’re in the right mood, we will move ahead,” he said.

Maggie Haberman contributed reporting from New York, Jonathan Swan from Washington and Alan Blinder from Atlanta.