Have you installed add-ons other than ublock origin?
Firefox
A community for discussion about Mozilla Firefox.
Yes. External application launcher, Hide members-only video on youtube, Youtube nonstop, Webserial for firefox, Tampermonkey, Per-tab volume control.
I can see how some of these might break shit so I disabled all but ublock, will see if the situation improves.
That's a lot, good to try without. I have only ublock.
Might be a bug, so we can troubleshoot to try to figure it out.
If you visit about:processes, is there any website or extension taking up a lot of system resources?
In addition to that, you can try launching firefox in safe/troubleshooting mode. 3 bars in the top right > Help > Troubleshooting mode
This restarts firefox with all addons, extensions, and themes disabled.
For further troubleshooting, also try:
Go to about:profiles, and create and launch a new one. This is a more complete reset, since it also resets all settings, about:config options, and similar.
After creating a new profile, you can play around with rebuilding your current firefox config, adding extensions and changing settings.
Nope
Maybe something you have changed a long time ago in about:config that does not work out with a recent update ? I don't know if it's possible
Or add-ons as previously mentioned
Or DNS over HTTPS configured in Firefox that does not work anymore for any reason
No problems whatsoever for me
On the PC, it's almost unusable. Android, no problems.