A lot of older PC games can run just fine on modern phone hardware. I’d buy a SteamOS version of a phone that has some modular or built-in set of buttons and analog sticks. I don’t know how the app ecosystem would work for sensitive things like banking but it’s mostly a minor issue for me.
I already despise having to charge my phone once a day. I might buy one if it were FOSS, but I don’t think I’d play many games on it.