Right.

Apple is perfectly capable of doing remote attestation properly. iOS has DCAppAttest which does everything needed. Unfortunately, it's never been brought to macOS, as far as I know. Maybe this MDM hack is a back door to get RA capabilities, if so it'd certainly be intriguing, but if not as far as I know there's no way to get a Mac to cough up a cryptographic assertion that it's running a genuine macOS kernel/boot firmware/disk image/kernel args, etc.

It's a pity because there's a lot of unique and interesting apps that'd become possible if Apple did this. Darkbloom is just one example of what's possible. It'd be a huge boon to decentralization efforts if Apple activated this, and all the pipework is laid already so it's really a pity they don't go the extra mile here.