I'm in the UK and yesterday, Nov 8, I saw that the One UI 4 beta / Android 12 is available in the UK for S20 devices.
So I did a full backup and installed the beta on my S20 5G running Android 11. Seamless installation and setup, no issues, all good. One app doesn't work at all now - known behaviour from betas with previous OS - which is Google Pay. Now's the time to check out Samsung Pay which will work on the beta, says Samsung.
The app I was most concerned about is Android Auto as I use this a lot in my car. Luckily, today it worked as it always has. Still with issues itself, though, as I keep reading about almost daily, eg, Google Assistant voice commands still very hit and miss: sometimes work, sometimes not. But a Google AA issue not a Samsung OS one.
In any case, all apps I've used today work fine, from social networking to browser to email to car navigation.
Overall, this beta is good. Appearance is crisper and phone performance overall seems faster. Only 24 hours since install so hard to tell yet re battery life. Observations to come.