Big Sur: Update to next version not showing up

My EFI is here: https://github.com/mbirth/hp-spectre-x360-4104ng-hackintosh

(Only change I've made in the meantime: csr-active-config to 0x67.) EDIT: Just updated the repo to what I have now.

When on Catalina, the update to Big Sur didn't show up even with the system enrolled into the DeveloperSeed, etc. So I manually downloaded the Big Sur installer and upgraded the system with it. (Which went smoothly.)

However, now, it still doesn't want to show the updates to the next builds. I'm on 11.0 Beta (20A5395g) and would expect to be offered the latest 11.0.1 Beta. But all I see is "Your Mac is up to date".

What's wrong with my config?