For a company I work for I needed to ship a machine through unknown channels and have some confidence that it wasn't fiddled with.

my threat model was reasonably technical engineer swapping drives for some reason, or someone claiming that the machine is "different". (no nation state shit)

after the machine was imaged, it would connect to our central config server, get its hostname and exchange keys which would be embedded in the TPM.

once the machine is shipped and booted, it'll check in and sign a challenge. any kind of action on the central API could have a challenge. Each machine is attested at least once an hour.

I'm not sure how "secure" it all is, but it seems to work.