I've not had any issues getting the beta to install. The issue I have is after. Once my machine comes up to the login screen it will not allow me to login. When I go to login with the password the password field does the little bounce back and forth thing like I've typed it in wrong. After so many times of doing this it tells me I can reset my password via my apple id. When I try that it then pops up a keychain screen telling me to track down my last known password through keychain. To see if it was maybe something with how the local login account is interfacing with my apple id I restored my device back to Catalina and created just a local account bypassing and not entering ANY apple id information. Multiple reboots and can login just fine. Then redownloaded and installed the big sur beta update. Same issue Upon coming to the login screen, I type in the password, and the password field just "jiggles" around like I've typed in the password incorrectly.