Hacker News works fine. Can’t vouch for the others, since I don’t touch corporate “AI” if I can help it.

Probably because of lagging behind in something they need to adopt from the mainline Firefox. Just checked in Firefox beta and I can access all of those sites perfectly fine.

Hacker news? That makes me suspicious that maybe there’s a different problem

You or the mull developer must’ve enabled a privacy improving feature like resist fingerprinting protection. Turn that off and try again. Use a search engine for steps to turn it off.