I-Firefox Isithangami Sokwesekwa

So I'm having issues playing 4K videos fully on one YouTube channel: https://www.youtube.com/@ClearviewDriving

For some reason anything above 1080p gives me bad stuttering but on other channels videos don't stutter or freeze when playing 1440p or 4K quality.

Firefox is updated, I don't use Extensions other than Ad Blocker and I have that off on YouTube anyway. Seems strange that it'd only affect one specific channel.

I have a very good gaming PC too so the hardware isn't the issue.

Concurrent with the most recent automatic windows update (may or may not be the problem), Firefox with duck-duck-go will not go to almost any site. All I get is a spinning icon or a blank page, not even any error messages. This was even true trying to go to this page until I restarted in trouble shooting mode. Until I can get Firefox working again I have been using Chrome with duck-duck-go. Note any search, i.e. 'hotels in Italy' or even 'MSN' do the same: spinning icon or blank page!! Any help would be appreciated. Also I noticed that my bookmarks were missing and there was no bookmarks drop-down on my tools line. I have run malware bytes and it showed clean, same with CCleaner. I have re-installed Firefox; no difference. Please help. and also, any way to find and replace my extensive bookmarks list? I have reduced my privacy to near zero and turned off firewalls and all limits I could find while testing for that. That did not change anything.

I've been having issues with the websites that I commonly go to no longer appear on the autosuggest list. Websites I haven't gone to for ten years appear when I type in a given sequence rather than more common ones. Website that I go to every day no longer appear.

Multiple websites suggest this sequence:

https://support.mozilla.org/en-US/kb/remove-websites-address-bar-suggestions

I follow the "clear all.." and nothing changes. How can I start anew and have FF re-learn my url history?