Some sites have been slower the last few weeks in Firefox and Edge.
In Firefox only, sometimes I get just the top bar of the page with the various tabs. Sometimes the page is blank. I have to press F5 to see the whole page. Sometimes I have to press F5 several times before the page displays. Sometimes I get Secure Connection Failed. I prefer Firefox because I made a bunch of security setting changes years ago - things like not saving passwords.
Edge consistently displays the pages, it’s just slow.
I have cleared cache and cookies.