Thanx everyone for responding. I just flashed V12.0.1.0.QJZEUXM eea and reinstalled UT 16.04 and meanwhile put 12.0.2 to download while waiting.
But with 12.0.1 now everything works.
Volte was not the issue because I am sure I cannot use it on my provider before requesting that service to be activated.

Anyway my Note 9 Pro can be called and call back. And sms works both ways.

So I guess V12.0.3.0.QJZMIXM was the problem.

@beyolf
Tomorrow I will try to install focal 20.04. Thank you for advice.
I am thinking of instaling 12.0.2 before since it will also probably work and it might contain some stuff that could resolve other potential issues.

Thanks everyone again for help. I will post here when I put 20.04.
Best regards to all!

@beyolf Finaly after a week of hell at work I found the time and I succsesfully installed focal 20.04.

I had issues installing it from windows since installer would stuck every time on booting to fastbootd, although phone was already in it,
but then tried in linux and all went fine.

So far all appears to be working. It appears that I cant sync Google Contacts, only calendar, but that is not really an issue since I wont be using this device for calls much and i can easily import contact via vcf card.

Thanx again for help