Aboubi Acrobatics

lets you flip in midair

Config

Once you hit the ground the mod automatically corrects your rotation to the original limits, or to looking straight forward if you were in the air for long enough. You can configure the amount of time in the air after which you'll be corrected to looking forwards and the amount of time the correction takes.

Manual Installation Instructions

(you should probably just use a mod manager like r2modman or gale though)

Download and install Bepinex 5.4.21
(if you have no idea what the versions mean try BepInEx_x64_5.4.21.0 and it might work. maybe)
Once BepInEx is installed, extract the zip into the BepInEx/plugins folder in the game's root directory.

have fun :3