In that regard Safari used to be a disaster and now it works alright but Firefox seems to be consistently worse. It's a shame because FF is very important to the future of the internet, in my opinion, and on macOS their performance is not that great. My backup browser for this sole reason is Brave. I wish that wasn't the case because the browser is stuffed with... things.. that I don't need or want in it so I always have to go and hunt down how to turn all of them off when I install it on a new machine.
To me a browser needs a UI that's small, unobtrusive but clean, no BS on the "new tab" page (I don't need random wallpapers loaded from who knows where or news) - just a list of bookmarks, speed and support for the few extensions I use (adguard, sponsorblock, bitwarden).
Please fix FF, I wanna use it as my main browser!