Firefox has bad performance for my use cases. It crashes around 50% of the time I open Gmail, and the other 50% of the time it crashes with any old tab. I know Gmail is bloated and less performant now but it's been my address for 15 years. Does Mozilla want me to deal with the constant crashes or abandon Firefox or abandon Gmail?
Interesting, it has to be something specific to your use case or hardware. I have Firefox open 24/7, 150+ tabs (Panorama tab manager), 4 Gmail account tabs (2 personal, 2 work) always pinned open, and FF just never crashes for me. Since Quantum was released it has just been stable.
Speculatively, it sounds like there's something about your specific system configuration, i.e., other apps or hardware, that's interfering with proper functioning of FF.
I've been using Firefox as the primary browser extensively, every day for a few years, and have never seen it crash. A few times I was running code with an infinite loop and managed to crash a tab process, but the rest of the app continued to run fine.
That said, I can understand your frustration - but I hope you don't give up on Firefox. In my experience, the switch from Chrome didn't take much time/effort, and well worth it for the peace of mind, using software that respects the user.