Hi! Welcome to the Samsung Members!
Note: As warned beforehand that you should back up all your data, and then yes, you'd need to wait for everything to reinstall.
These are the steps below, but the stable release should be relatively soon; why leave beta?
Credit:
@AndrewL"Before downgrading via the Smart Switch app on your computer, please head to the Samsung Members app on your phone > Settings > One UI Beta Programme status, and select 'Withdraw'. Following this step, head back to Smart Switch, and the downgrade option should be available. Let me know if this helps."
https://eu.community.samsung.com/t5/galaxy-s25-series/how-do-i-downgrade-from-one-ui-8-beta/td-p/124...Via a PC and Smart Switch
