He would, and does, play Fire Emblem. I've seen him playing with Obama and Biden on YouTube.
From his general mental faculties and his extensive history of assorted sex shit, I'm going to say that if Donald Trump were a gamer, that he would probably spend most of his time on Bubble Shooter and erotic visual novels.
I found a YouTube link in your comment. Here are links to the same video on alternative frontends that protect your privacy:
maybe some flashy casino type games that give a dopamine hit, edit: oh you mean like a real gamer.. maybe some pro golf games
This is the only correct answer. He would only ever play shitty casino games
LoL, his first impulse to start shitting on everyone else in the match would fit right in. He would only play AP Teemo and wander around planting mushrooms. "We love trolling junglers trying to get a kill don't we folks?"
In my mind-palace Trump is a Sega gamer obsessed with Sonic and Shenmue, but in reality it'd be something chudy and boring like Fallout 4 where he's evil in every playthrough.
He would spend all his time installing HOI4 mods and giving up 15 minutes into every run.