Firefox

Have you tried a fresh profile? If you have the same issues as before then it sounds like you're running your old one too. And it could also be a single one of those add-ons bring the issue, so try figure that out too if the fresh profile doesn't do the trick.

Unfortunately this is 100% an issue with your system and not Firefox.

This reeks of a problem with your system, not Firefox.

Are you using an HDD or SDD?

I would disable any custom fonts you have added to Windows too. Or at least check them for font conflicts. And check the reliability reporter to see if it says anything in particular about the days when FF crashes.

EDIT: I also just noticed you have a VPN in your plugins. The Firefox VPN used to behave pretty wonkily if it got a bad connection and could look like everything was frozen. This would be my immediate prime suspect if you think it’s extensions.

I also agree a fresh profile is a huge pain but worth a shot if all else fails. It can make a difference when you can’t trace down what about:config you boned horribly haha.

I recently spilled water on my mouse. Everything seemed fine, but ff kept hanging more or less as you describe. Swapped out the mouse and it was fine.

Probably isn't your problem, just thought I'd let you know.

I'd run a memory test overnight.

Not a debugging help, but: I have the same issues. Especially the tab thing. Open one, try to open a page, nothing happens. This is especially bad on android for me.

Number 3 is something Firefox has done for ages, even before quantum. It will refuse to start of there is another, non-responding, instance running. I think they actually added a dialog for it that sometimes works.

Number 1 is something I see on Linux every now and then. For me, only the mouse input is ignored then. But sometimes Firefox just hangs without crashing (Probably some loop somewhere went nuts).

I do not have solutions for this. I just want to add, that it probably is not because of OPs system.

You can try a fork of Firefox like Waterfox or Libre Wolf just to see if the problems are repeated there. They use the same base engine but tweak different things.

Works fine on my Mac and Linux machines. Maybe this is a Windows issue.

You could try a VM with just Firefox to see if there's another program interfering with it?

Is it feasible to reinstall Windows? Always a fresh start fix all these problems.

give nighlty I try on my second old phone were Firefox was not usable is now working quite well (for the old hardware snapdragon 660 and 4 giga of ram )the only sad part is opening or focusing url bar (which still show home )is painfully laggy and slow

Are you running this on the same PC/OS install that you were having problems on previously?

Something that may help with diagnosis is to try a portable version of firefox. If the portable version works properly and your installed version does not then it could be either some setting or library that is having problems.

Would also try running as a different user to see if maybe the issue is with something in your user profile.

I once uninstalled a program that took a library that Firefox was using with it and had similar results. Drove me goddamn mad trying to figure it out. If it’s anything like that, I recommend just going back to chrome, or trying Firefox in a VM to pick it apart if you’re feeling incredibly motivated. Took me days to diagnose and a minute to download the fix.