Clearing Cookies seems to fix it, but that's annoying to do every time it stops working. It seems to be working fine on Firefox, but I also don't use Firefox as my main so I'm not sure if it would stop working.
Enhancer for YouTube by Max RF doesn't work on Waterfox for some reason, but works on Firefox and Floorp so it isn't Gecko based. It started around July 8.
Edit: Seems to work in Private Mode?
I can also get it to work by disabling it, loading the video, and then re-enabling it.
Edit 2: I cleared Cache and Cookies and that seems to have fixed it for some reason.
I use my browsers without hardware acceleration, because it seems to use less power according to my UPS and HWInfo.
I've been using Brave without hardware acceleration for a couple years now and for some reason the FPS is now unstable and won't push past 50 FPS and won't go away unless I restart the browser. It seems to occur when more than one window is visible at once. Before then it did not have this issue. I've tried clearing cookies.
I used videos and TestUFO to check the frame rates.
The biggest changes I remember is the MV2 changes and Reddit RES account switcher changes, which I tried to find alternatives for. I've removed those extensions as they didn't work correctly.
Waterfox/Firefox do not have this issue.