This is exactly why I decided to not update today... I just removed the beta profile to avoid an update all together until the final 13.0 version is released. I’m always a day 1 purchaser of new iPhones and want to avoid any complications or data loss.
Some have suggested 13.1 will be released on launch day, but I highly doubt that. I expect it to launch much sooner than a normal x.1 launch, but still at least a couple weeks after 13.0.
Some have also suggested the beta 8 is the GM and that is almost certainly false. They are still working on 13.0, but they can’t run two simultaneous 13.x betas at the same time. They are limited on what they can change now with 13.0 anyway, so why not use the massive pool of testers to test 13.1.