Im thinking of connecting an Xbox one controller using a phone controller mount. What are the best front ends/backends to use?
Simplest is Retroarch or Daijisho.
If you really want to get fancy, consider getting one of the cheap handhelds with build-in game controllers, like an Anbernic RG353 or Retroid Pocket.
I was going to get one of those, but I have this s22 lying around without getting used. How does the S22 compare to those, power wise?
A lot of handhelds reuse older or lower power chipsets with surplus stock. The S22 should be much more powerful, even if it’s the Exynos variant. If it’s the Snapdragon variant, it will handle PS2 and Gamecube with no issue, Wii, 3DS, and probably even Switch games (at least what’s currently playable on Android).
Just get a good controller. Bluetooth is fine, but if you get something like the Razor Kishi it’ll have less latency as it plugs right into the USB-C port. There’s probably other similar ones but I haven’t used any telescopic controllers in a long time so not sure what’s on the market.
The only bad thing I can think of is that since the snapdragon variant is on the SD8 Gen 1 chip, it’s known to be prone to overheating on longer sessions, but that’s only going to happen with really intensive emulation that pushes it to the limit (mostly highly upscaled PS2, Switch, Gamecube).
Lemuroid is much easier and pleasant to use than Retroarch.