I have seen folks talk about a pain point for using FF (or forks) being related to YouTube being super slow. The about:config settings the article mentions did seem to lead to YouTube loading faster on both my FF and Zen-Browser installs. So maybe this might help for others that specifically don’t like to use FF as their main browser because of YouTube.
For those that just want the settings:
gfx.webrender.compositor.force-enabled (set to true and restart FF)
If on AMD GPU, this extra setting is supposed to help reduce CPU usage:
media.wmf.zero-copy-nv12-textures-force-enabled (set to true and restart FF)
*edit - per Zak in the comments. The AMD setting is Windows specific.
I am not sure, all my browsers have uBO. But the article didn’t mention anything about adblockers. Google has made YT slow for FF no matter if the user has one or not (which is a known thing). But it was pretty noticeable when I loaded.