Recently Vimeo became a number one house for me in terms of videos. Its constant ads that you cannot stop or skip that least somewhat of 45 seconds (!) steers me away from YouTube. And quality on Vimeo never disappoints, I mean has there even been low quality vid on Vimeo?
I also eliminate ads completely using ublock. Not everything is vis a vis. If youtube was a bastion of free speech and didn't demonetize controversial creators then I would consider supporting them.
I have YouTube premium as well (which I generally like), but just today noticed it is now showing me ads when the video is embedded on other web sites. Not cool. Have you noticed this?
I just tried that, not realizing that VLC could do it.
Unfortunately, it seems to play 1080p videos at 360p, which, not to be a snob or anything, isn't watchable for me. Well, I'd prefer an ad than a really blurry video.
If you use Firefox on your phone, you can install uBlock Origin (blocks youtube ads without fail) and the "Video Background Play Fix" addon which allows you to play youtube videos with your screen switched off.
Since you touched the issue: I can't seem to play anything on Vimeo and for a good while (maybe this entire year?).
I think it's related to NoScript/uBlock/Firefox's privacy settings because the only way to get videos to play is to restart my browser with addons disabled.