Found a gem for YouTube (V3 extension: addons.mozilla.org/en-US/firef) — which brings the old interface (from the start of XXI century) back. It is more clean, if it is even possible to say "clean" about YouTube interface, and also it is faster as hell than the "modern" one.

On the my box (Thinkpad X220 with i7, 16 Gb of RAM) the usual YouTube lags as hell, even while I'm scrolling. The old interface — works almost instantly, lol.

YouTube with old interface from 2013 (provided by V3 extension). There is a main page on the screenshot.YouTube with old interface from 2013 (provided by V3 extension). There is a page with running video on the screenshot.
0

If you have a fediverse account, you can quote this note from your own instance. Search https://mastodon.bsd.cafe/users/evgandr/statuses/116019808958890585 on your instance and quote it. (Note that quoting is not supported in Mastodon.)