I've been an avid Mac user since the Apple IIe and this "new improved" completely broken version of Safari is the first time I've seen this huge of a failure. It's not even a Beta version. It's not even Microsoft awful - it's a total embarrassment. It's very clear no one even tested it before release.
A huge number of websites no longer open. The problem frequently seems to begin after attempting to login - the redirect confuses the browser.
I still getting this problem daily and for whatever reason it honestly seems to be getting worse. I'm not even sure what kicked it off but I think it might go deeper into the system networking.
I'm seeing the problem happening in other browsers such as Chrome and so on too. I don't use them as much so I didn't notice until now, but I'm running into the same issue.
So I think it has to be in the lower-level MacOS networking code. Have no idea why it's affecting some and not others, but it's definitely real. My wife's computer, also an M1 if that matters, started doing it last night and is still going.
It's not site-dependent either. Sometimes Google won't even load, just refreshes in an endless loop. Then other times, it'll load. Same with nearly all URLs. This really needs to get fixed as Apple....you basically just broke the Internet for many of us.