Since YT in my FF is heavily modified to be not awful, maybe the regression is in something my add-on stack is blocking.
looked this up out of curiosity. the only thing resembling a description is "Combine small plugins, expanding the possibilities of YouTube." which is pretty useless.
what all does this do?
https://i.imgur.com/lMKaJ5t.jpeg
After putting the number of videos in a grid row back to a useful number, things I especially like are changing video thumbnails back to a still that's actually from the fucking video, instead of a misleading click-bait image. I also like the option of changing all caps and removing emojis from video titles. It also has options to automatically remove a bunch of the stupid shit YT pushes in the UI I don't want to see.
After I got it set up, I found it literally shocking how much better YT is - yet in many ways, it's just restoring YT to the way it used to appear and work when its focus was user-centric instead of user manipulative. Since about ~2016 we've all been slowly frog-boiled by YT making the site slightly more annoying every month through iterative A/B testing optimizing for ad revenue. I literally can't go back to using stock YT now.
Each module has an info link which points to its entry in the wiki: https://github.com/raingart/Nova-YouTube-extension/wiki/plug.... Since I'm not familiar with YT's terminology for labeling all their UI elements, it initially took a little experimentation to see what some of the module options do but it's quick to change a setting, tab back to YT, refresh and see the result.
I did have issues with YouTube recently - I was getting some of the same symptoms described in the Reddit post. But tracked it down to me changing my user-agent to Chrome, which I had forgotten about. This was also causing issues with reCaptcha and Cloudflare-protected sites.