The best situation would be that the ARM processor is powerful enough to run an x86 emulation layer so you can directly play the same games you play on your PC on your phone or tablet. I’ve been experimenting with box86 and FEX on postmarketOS using a OnePlus 6T and already Steam and several lighter weight games are very playable, but the next generation Snapdragon chips should be able to take it a lot further when it comes to running more demanding games.
I’m pretty happy with my Arc A770. It’s in my secondary build because it can’t do 4K 144Hz, but for the price it has been a great 1440p card and has solid Linux support. I would rather buy Intel than NVIDIA when it comes to a gaming GPU because of NVIDIA’s poor Linux support.