I've seen two people have issues on revanced. Both with buffering issues. Also one with background playback.
When vanced was abandoned, it also limped along for a long time. Youtubes ab tests make stuff break gradually for only some.

When I switched and when I made those people switche, all problems went away. I've also found the experience nicer on Morphe.

Best I can tell, youtube revanced is a dead mod walking.

PS: Downloading has never worked, and afaik can't. Morphe has nice integration for an external download app if you're interested. You can enable a mod to rebind those buttons.