Just got One UI 7 BETA on my S23 Ultra. So far, I can say it is INDEED the best UI after One UI 6, but I still think that one was a little better. I just feel like the home screen is now LOADED with apps and icons, leaving very minimal space.
Open Samsung Members, you should see a noticr banner with title "One UI 7.0 BETA for S23 series". Click on it and press join/enrol, the wait about 5 mins and Goto settings > software and update, and it will be downloading already if you're connected to WiFi
Someone posted about this earlier this morning, the answer given was that the members app forum was giving out issues from time to time due to server errors and to ignore the banner post as the beta was finished.
The homescreen is a design of your choosing. I don't really see how it's overloaded unless you customise it that way. Functionally, it's no different from any other OneUI, which is what makes it pretty seamless.