Firefox

You could have system monitor open in order to check what happens with Firefox process when the browser freezes.
See if you can find a reproducible way to freeze the browser. That way you can start to narrow down the cause of the issue. You could stay on the older version of Firefox and only update once the next version is released.

Try to run your Firefox profile in troubleshoot mode to see if it's caused by an extension.

https://support.mozilla.org/en-US/kb/troubleshoot-and-diagnose-firefox-problems#w_3-restart-firefox-in-troubleshoot-mode

Alternatively create a fresh Firefox profile and see how it goes there.

firefox -ProfileManager

If it turns out it's really Firefox doing it you can downgrade to a previous version (but make a copy of your ~/.mozilla dir first, and don't go too far back with the versions). Garuda is Arch-based if I'm not mistaken so you can install and use the downgrade command line tool from AUR.

I have seen no problem with the latest version (118.0) so far on Linux.

Maybe you should add the OS you are using.

Have you tried a new profile to see if maybe one of your extensions might be involved?

https://profiler.firefox.com/ might be useful. about:profiling too. Maybe also about:logging about:processes and potentially others in about:about

I'm experiencing this too. Particularly in outlook web (which I am forced to use for work). Frustrating!

Test your ram, just in case.

There are of course a myriad of reasons for which you'll get a lot of ideas. Some have already suggested running memtest.

I'd suggest a full hardware "scrub". Open the case, clean out all dust with a blower (don't forget the PSU!!!), wiggle or remove-reinsert all electrical connections, especially CPU and RAM, but also GPU and expansion cards, storage (data and power), etc etc. Basically if you can plug it in, give it a wiggle to break any oxide layers or as I said remove-reinsert. Might not even hurt to double check your CPU and GPU thermal paste contact if it's old and might have dried out.

Then double check your overall air flow. Your CPU might be cool as a cucumber, but maybe your m/b is getting too hot from lack of air flow. Ironically its possible that a cool CPU = slower fan = less airflow around SB chips and power chips.

I was having escalating browser freezes from random weekly to random daily to random hourly or worse, on a system that was stable for years. I did the above and added another case fan for better MB flow. Now my CPU runs cooler, the CPU fan runs even slower, and I've been rock steady for 2 weeks without a single freeze-up.

Try using a different profile? (about:profile)

If you've tried all other things, you can try to refresh Firefox. It's the nuclear option in that it will remove your customisations, but is likely to resolve issues potentially caused by them.

Then don't sue it.