Personally, I’d just go with the higher-resolution display, if you notice your GPU struggling at that resolution, you can still turn down the render resolution of the game, but you’d still be on a larger monitor.
The larger issue when gaming is probably that some games don’t play nice with ultrawide monitors, so your mileage may vary.
Even stuff like the Steam Deck can play emulated Switch games, and that’s an x86 PC, a machine with a more similar architecture should absolutely have no problem with it.
Doesn’t mean I’m banking on backwards compatibility though.
It completely depends on the games you play.
Personally, I’d just go with the higher-resolution display, if you notice your GPU struggling at that resolution, you can still turn down the render resolution of the game, but you’d still be on a larger monitor.
The larger issue when gaming is probably that some games don’t play nice with ultrawide monitors, so your mileage may vary.