I had the same issue. The following from another user worked for me. I took like a minute for it to update before I could download. I had the same problem that after installing the public beta profile for Big Sur, I was only offered an upgrade to the latest beta from Catalina.  So I ran sudo as root via terminal and typed the commands there: open terminal sudo -i enter root password /System/Library/PrivateFrameworks/Seeding.framework/Versions/A/Resources/seedutil Unenroll from the Beta Program  /System/Library/PrivateFrameworks/Seeding.framework/Versions/A/Resources/seedutil unenroll Enroll in the DeveloperSeed Beta  /System/Library/PrivateFrameworks/Seeding.framework/Versions/A/Resources/seedutil enroll DeveloperSeed Close and re-open System Preferences > Software Update The new Beta should now show up