So, I went and googled “Trump cheats at golf” stories from 2010-2020, and these are clips from the first three results that turned up - and there were a LOT of results!

Yahoo Sports:

Trump hit a ball into the lake. But when the other players weren’t looking, he got out another ball and hit another try, although that too went into the lake. “So he drives up,” Faxon said, “and drops where he should’ve dropped the first time and hits it on the green.” […]

Tirico remembers hitting one of the best shots of his life squarely onto the green, but when he walked over, the ball was 50 feet away in a bunker. “Trump’s caddy came up to me and said, ‘You know that shot you hit on the par 5?’” Tirico says. “‘It was about 10 feet from the hole. Trump threw it in the bunker. I watched him do it.’”

Golf.com:

He throws it, boots it, and moves it. He lies about his lies. He fudges and foozles and fluffs. At Winged Foot, where Trump is a member, the caddies got so used to seeing him kick his ball back onto the fairway they came up with a nickname for him: “Pele.”

Trump said, “So, where does everybody stand here?" [Trump then claimed he was at] “Four for a three.” Faxon had to laugh because Trump was actually putting for a seven, but he was claiming it was for a four,

They call him on it, but he just shrugs and cheats some more. It’s ruined his reputation in the golf world. Ninety percent of the people I interviewed — on and off the record — say he openly cheats.

he was right of the green but a little bit down the hill. He didn’t think anybody was watching, but I was. I saw him make a chipping motion from the side of the hill but no ball came up. Then he walked up the hill, stuck his hand in the hole and pulled a ball out. It must’ve been a ball he had in his hand the whole time.

He makes sure to hit first off every tee box and then jumps in the cart, so he’s halfway down the fairway before the other three are done driving. That way he can get up there quick and mess with his ball. So this one time — we were on the 18th — he hits first, kind of blocks it right, and jumps in his cart and starts driving away. My guy pures one right down the middle. I mean, I SAW it go right down the middle. One of his best drives of the day. But by the time we get to my guy’s ball, it’s not there. We can’t find it anywhere. And Trump is now ON the green already putting! Where’s our ball? And then Trump starts yelling back at us, “Hey guys! I made a birdie!” He’s holding up his ball and celebrating. And that’s when we realized. He stole our ball!

Trump, his partner, came over and secretly knocked the ball on to a part of the green where Dunleavy could putt it. Dunleavy picked it up and put it back where it was. “That’s when Donald starts yelling to the other two,” Dunleavy recalls. “He goes, ‘Guys, guys! I wanna tell you how great a guy Coach is. I knocked his ball over here so he could have a putt at it. But then he put it back! And that’s why he’s an unemployed coach and I’m worth $13 billion.”

The New Yorker:

“He’d declared that the [Bedminster] club should start having senior club championships for those 50 and up, but he forgot that one of the best players at the club had just turned 50,” Reilly writes. “Having zero chance of beating the guy, he went up to his Trump Philadelphia course on the day of the tournament and played with a friend there. Afterward, according to a source inside the Bedminster club, he called the Bedminster pro shop and announced he’d shot 73 and should be declared the winner. The pro, wanting to stay employed, agreed. His name went up on the plaque.” This turned out to be a double con. When someone from the Bedminster club called up Trump’s caddy at the course in Philadelphia and asked what he’d shot there, the caddy replied, “Maybe 82. And that might be generous.”

well-known sportswriter, Michael Bamberger, reported that Trump won the 2018 club championship at his West Palm Beach club without playing in that tournament, either. And Trump admitted to Reilly that at least some of those eighteen club championships weren’t championships at all. “Whenever I open a new golf course, I play the official opening round and then I just call that the first club championship,” Reilly recounts Trump as saying. “There you go! I’m the first club champion!"

“If you’ll cheat to win at golf, is it that much further to cheat to win an election? To turn a Congressional vote? To stop an investigation? If you’ll lie about every aspect of the game, is that much further to lie about your taxes, your relationship with Russians, your groping of women?"