Also- regardless. NOBODY besides samsung themselves can provide such information, being a forum for customers- we have the same information you do, we cant give accurate dates.
But dont stress. Ui8 is pretty much exactly as ui7. Im on beta and its not as "huge" as the ui6 to 7
Betas are usually only for the latest gen devices. Sometimes the second newest gen get them. The s23 series is 3 generations old, I doubt it will get any betas
A Beta program is not a software update, it's a testing software to see how users get along with it and to report bugs and suggestions. If you wait for the stable version you are not missing anything.