Yes, this is one of the affected bugs, but do read the other bugs linked from it, e.g. https://bugzilla.mozilla.org/show_bug.cgi?id=1010527#c51
> Even wirh webrender, EGL and dmabuf all enabled, performance is still not at par with chrome. Bug 1684224
which shows 5x higher FPS in Chromium than in Firefox.
There will be more to do until general parity, even past FF 94.
This is literally one of the big things changed by what's described in the article (for those still using X11; it's already been solved for quite some time on Wayland)