Total silence but in calls a floating notification

Notification, Vibration Off

DND with custom settings specific for the gaming mode

Please be more explicit, custom settings are very vague

Restrict usage of swipe to screenshot

Turn off auto screen off

As in a separate set of settings for DND that are different to DND without gaming mode on, i.e. with regular DND to block all calls but with gaming mode to allow favourites

There is already caffeine mode

Fps meter maybe if possible

Sudo rm -rf fast button

Block all background processes to speed up the game