Firefox and Firefox-derivative browsers have and continue to be seriously sluggish and memory and energy hogs. This should not be swept under the rug.

Even today it is difficult for me to use Firefox, Mullvad, etc. When I used to use them, almost every time my machine became slow the solution was to kill Firefox.

EDIT: It's true folks, I would love to be able to use Firefox as my primary browser. But all my experience with it (and I used it for more than a decade) has been dogged by its sluggishness.