Psst. Hey you. On Linux/Steam Deck, like me. Got a secret to share that'll make finding xfconfig and playing with your bullet glow settings easier on ya.
steam>steamapps>compatdata>2293977369>pfx>drive_c>users>steamuser>AppData>Local>Xeno_Fighters_R is where my xfconfig.ini file is located. Maybe the same location (or at least one under some sort of number in compatdata) exists for you, too? If you use ProtonUp-Qt, double-clicking the version of GE-Proton you use lets you view exactly the current App IDs for the programs you run with it.
Have fun. :)