It used to be possible right ? doesnt have to be a strictly youtube focused site either, being able to grab url from other sites are always a plus, only suggest apps that are on fdroid (main repo) .
Also for those who dk and might find useful you can use webtor to get a network stream url from magnet links, tho i wont suggest it as the lag and experience is abysmal and misses important functions like seeding .
Dunno about an extension, but I use tubular (a newpipe fork with sponsorblock) on android and set it to open all the links for youtube videos on it. It has been working quite good, although lately I’ve been getting some videos not showing on tubuluar. Probably some change on youtube break this kinda of app.
its cause tubular uses newpipe extractor for fetching videos and itbwas broken for a few days, got fixed yesterday tho so will be solved when they merge upstream changes, id recommend using newpipe over tubular, its what i use .