What are your current firmware details?
Settings > About phone > Software information > Build number
@Blkpanther: If you have withdrawn from the Beta via the Members app, then you may be able to rollback to the previous software via the Smart Switch app on your home computer. If you don't already have it installed, please follow the link below, select 'How Do I get Smart Switch On My PC or Mac' and download the relevant version.
Once installed, open Smart Switch, connect your S21 device via USB cable, and look for a 'Downgrade' option on the landing page. Let me know how you get on.