In my younger days I used Firefox as me default browser on Windows.
It was fun to tinker with.
The add-ons were especially interesting. Things like greasemonkey let you lay over a custom script over the websites you visited.
But when I started to concern myself about the security of all this tinkering, I stopped with running script that a very sympathetic Russian kid had created.
So at that time I switched to Google Chrome and now I'm using Edge Chromium.