For what is worth, I use Firefox (plus many extensions including UbO) to do banking, connecting to government sites, medical stuff, and other non-trivial-surfing tasks, and the worse thing I encountered ever, aside the occasional harmless misaligned box or font, were a local hardware store whose search doesn't seem to work, and an online musical instrument shop (thomann.de) whose pages scripts sometimes hang, but as I wrote I run a lot of extensions so I'm not sure if those are FF issues or not. Everything else, and I mean really everything else, just works fine.

Accept and let go of the fact that good people you love make bad life decisions. Life becomes much easier after that.