Not really an answer to your question, but I’ll share my approach. Youtube channels have rss feeds, so you can “subscribe” using any rss reader, and don’t need to login.

So I just use firefox with the following addons. A seperate youtube container + adblock + in-video ad skip + age verification skip + feedbro as rss reader.

I’ve seen bright IR emittors, that can oversaturate some cameras

For self hosting?

Looks like the author is still active and looking for funding: https://github.com/TachibanaGeneralLaboratories/download-navi

But development seems to have stopped indeed. There is a fork, with new developers, that is actively being worked on: https://github.com/Davilarek/download-navi

GIMP is such a workhorse and a pleasure to work with.