Please go to service center for rollback to previous version through Odin and manually update your's device. If you like please accept it's as a solution it's help to others users also, click on 3dots in my reply section and click on accept solution. Thanks.
If you have withdrawn from beta, you are mostly unlikely to get the stable update. Once you withdraw, you are expected to rollback to one ui 7 stable and then update.
That's what I know. Because your device stays on beta itself even when you withdraw. You need to visit service centre for assistance
Next time, do remember - think before you opt for beta. Once you enroll and install beta, you should stay on beta till stable update is received.
