If I remember correctly, last year it was weeks later before Samsung pushed the update to get people off of the beta after everyone had got the update. Samsung sure knows how to treat their customers.
Thank you for your post. The stable version will be available soon, so please keep an eye out for the update. We appreciate your contribution to the beta program.
One UI Beta Team
Nope sim cards determine the network, all the carrier does is provision your use of an unlocked phone on it. Your software is pointed towards samsung severs which is how you got on beta to start...also how you get a majority of Normal updates a lot earlier than carriers