Device: Mac Pro 2017 Intel version
MacOS: 13.0
xCode: Version unknown
Issue:
No update available on MacOS 13.0 Beta even though the latest Beta was 13.4
Solution:
It looks like that xCode not being up-to-date can lead to MacOS not finding new updates.
Specifically, this was related to MacOS 13.0 Beta not being able to update past this while there was a pending xcode update.
Since xcode was only installed on my 2017 Mac Pro for experimentation purposes it hadn’t been updated in quite some time.
Deleting xcode and restarting jumpstarted the MacOS update process into 1) finding that an update was actually available and 2) downloading and installing it.