Software Update finds no new updates. I re-installed the profile with Developer Beta Access Utility, which causes Software Update to launch afresh. It seeks, shows "Finding Update" and never finds one, but doesn't time out either. I have 21A5522h installed. This hasn't worked for the last few beta releases.
latest Monterery beta releases not found
is this because I need to download the .ipsw file and use Recovery? That wasn't the pattern on the earlier betas, was it?
Boot into Recovery, then it's obvious.