I saw it in a review, so idk

Some models support it. I had one from PowerAdd

They are, kinda. You can buy a power bank that can be charged and still output energy

I tried using gamescope again but with passing some flags, which I found on protondb

eval $(echo gamescope -W 2560 -H 1440 -r 165 -f -- "%command%" | sed "s/2KLauncher\/LauncherPatcher.exe'.*/mafiadefinitiveedition.exe'/")

Thanks for suggesting that, but it unfortunately didn’t work and the problem hasn’t changed