I know you can do this with the official youtube application for android, but is there a way to do this with firefox on android?
I dont wanna use youtube application cuz of adds

In browser on PC you can right click the video to select loop - that functionality should probably exist in firefox on android too.

Alternatively, there are applications you can install on Android to block youtube app ads - been awhile since i've had an android phone but a couple years ago I accomplished this with something called "vanced".

Yeah i'm aware on PC, but there's no option on android.... maybe i need an addon to block them