And what? If someone can live with ads, they can stay. Otherwise anyone can install Firefox. I was all-in Google since the beginning of Gmail. And switching to Firefox was completely painless. Everything works the same, times of website incompatibility are long gone.
I really wish Firefox implemented easily switchable browser profiles. I am use Firefox mainly but for work I’ll still use edge so I can use this feature.
I don’t know exactly what part of a separate profile you are after, so this may not be a 100% substitute, but I found container tabs in Firefox to work quite well (with some extensions to imorove UX). It’s still the same profile though, so passwords and history are shared.