So what's strange here is that these hangs are weeks after Firefox 95.0.2 was released. That points to either DoH provider or some HTTP 3 server triggering the buggy behavior at scale. Either is fairly scary.
I lean on this. I have a 95.0.1 on ubuntu and got the problem for about 5 minutes. Killed firefox, waited a while and tried again and it worked. So it's not an update issue. A centralized service somewhere failed. Which is, indeed, scary.
It looks like it probably was a client and server interaction. Somebody (Google, Cloudflare...) switching over more of there infrastructure to http3 triggered it in more clients.
