Among the Firefox Wayland bugs, one of the top crash bugs is over a lost connection to a Wayland compositor. For dealing with it is to have a proxy between Firefox and the Wayland compositor to cache messages and prevent compositor message queue overflows.
while this is good on theory, when your CPU is being absolutely hammered, you need to re-adjust priorities to make a system responsive again, it’s actually not a simple thing to do without a context aware scheduler. Even though EEVDF is pretty good, it still struggles some times
My PC with a 133MHz Pentium 1 processor was pretty responsive all the time back in the day. It’s definitely a solved problem.