In the Members app tap on the "One UI 8 S25 Beta" banner, then tap the 3 dot menu at the top right. There you will find the "Leave One UI 8 Beta" button. I assume you tap that and then check for a software update and it'll bring you back to 7.
Good luck. I tried from my Mac using smart switch. After an hour of backing up, then starting the downgrade progress which took another 1-2hrs just to fail. Probably would work if I tried it again or used a PC but it's not worth restoring the phone and hoping the backup puts everything back correctly.
Only bug im having is the share sheet / share button crashes whenever I try to share something. Happened in beta 1 and 2. Desperately waiting and hoping beta 3 will fix.
