there is a fork of youtube app newpipe called bravenewpipe that allows rumble and bitchute, you need to paste links in search but can click and subscribe in app etc
newpipe wont add support for those platforms as they are woke kek
heres the android apk all open source https://github.com/bravenewpipe/NewPipe/releases/download/v0.25.1-2.1.1/BraveNewPipe_v0.25.1-2.1.1.apk