There are also some new macOS privacy & security features that can give Safari problems with some sites. I don't recall the specific feature names, but there is an IP hiding/masking feature as well as another feature that some sites may not like.
Chances are if you use a third party browser, you won't have any problems because those specific macOS privacy & security features I mentioned only apply to Safari.
If you are using any anti-virus apps, cleaning/optimizer apps, third party security software, or a VPN, then they could also be causing a problem....none of these types of apps are needed on a Mac.
I'm sorry that I cannot recall the name(s) of those new features.