Is the performance hit sorted yet when opening a page? For me Firefox used to hang for a second or two doing something? Just a blank screen with the progress bar paused around 20% or so and apparently nothing happening...(DNS? HTTPS handshake?) and then it would kick off and load normally. Happened on mobile(android) and desktop(windows, Linux, macros).

On chrome-based browsers the same pages on the same computers on the same network would load in within the blink of an eye, with no pause.

I eventually gave up and went back to chrome after Firefox being my daily for years. I prefer the dev tools in chrome anyway TBH