Just as another anecdote, mine failed to launch a local website I was debugging. That's my first time opening FF today. I opened JetBrains Rider (on Fedora 35)

Just as another anecdote, mine failed to launch a local website I was debugging. That's my first time opening FF today. I opened JetBrains Rider (on Fedora 35) and debugged my site (Alt + F5) and it launched to a blank page with FF locked up. So this isn't to do with ME specificially trying to connect to an external service.