I have been seeing many people complain about one or the other issue after completing OneUi 7 update. And most of the people with the issue have downloaded via mobile data or a slow WiFi.
Update package is over 4.4GB. And if connection was interrupted during download it might cause issue.
I downloaded via a high speed WiFi and have not faced any issue so far. So please make sure you have access to a Good and stable wifi network to download update file.
