Rendering performance is one of the few things left that Chrome has up its sleeve as an edge over their competitors (mainly Firefox), at least on Linux. Out of the box, Firefox has terrible rendering performance, not to mention hw-accelerated video decoding. Now, Chrome is not a whole lot better out of the box, since it still applies old "Driver bug workarounds" that have long been fixed in mesa/GPU drivers, but this…
Seriously, FF on Ubuntu causes 100% CPU usage when watching YouTube in 1080p. Meanwhile Chrome on Windows eats maybe 6-10%. How is this not #1 priority to fix?
I've used an addon for a while which fixed it by forcing YouTube to serve h264 rather than vp9 content, as hardware accelerated decoding of h264 worked but not vp9. But lately it hasn't worked well. Haven't investigated if it was due to newer content only being vp9 or if the addon stopped working.