I have been using Firefox + Chrome + Edge on a daily basis for years just because it helped me mentally separate my browsing areas that needed to absolutely not

I have been using Firefox + Chrome + Edge on a daily basis for years just because it helped me mentally separate my browsing areas that needed to absolutely not collide with each other. I remember a few years ago, Firefox was making my browsing experience miserable: incompatible rendering, high memory/cpu usage, and it just felt "old". Flash-forward 2016 or 2017 (don't remember precisely), two things changed at the same time: Firefox started feeling less poorly developed, Google started making changes in Chrome that really bothered me on a more ethical / privacy level (general stance on default values in privacy/security settings, increasing hiding stuff from me such as in the address bar or the network tab, features added "for my own good", heavy use of dark UI patterns, etc.). I felt I needed to get out of Chrome rapidly, and there was no way it was going to be Edge (trust had to build, and it takes years), so I started re-using Firefox more heavily while anticipating I'd be frustrated. That day never came: the months passed and Firefox kept getting better and faster. I guess I had my epiphany when I discovered there was a hard profile switcher in Firefox, which makes separation of concerns both easy and efficient to implement. This is not the "containerized tabs" thing (which I could never trust, don't ask me why) but the actual hard profile switch, that makes it impossible from one Firefox instance to access what happens in another instance simply because the separation is controlled by the operating system. Now, when I click the Firefox icon, a list of profiles is shown on the screen: (browsing, work, facebook, linkedin, banking, shopping, training-X, training-Y, etc.). I select the profile and the browser is themed in a way that I instantly know which profile is in front of me. I also wanted to make sure than if I mistakenly open a link to a third-party website in my "work" or "banking" profiles, that link would never actually be queried. The trick is very simple: I configured a proxy that points to a non-existing service (127.0.0.1:9999) and added the list of trusted domains (work + banks) in the proxy exceptions list. Anything else gets clicked/opened in these sessions gets directed into a black hole. If you're interested in reaching this setup, simply replace your firefox shortcut by adding: -ProfileManager at the end of the command-line. From that point on, a window with a list of profiles will be shown everytime you click the Firefox icon, and you can have truly separated browsers running.