Finally got to the stage where the ACME certificate profile is successfully installed. However, the public key/certificate itself isn't appearing in the System Keychain. I'm not sure if this is normal or if it's an indication that something went wrong after the profile installation. Unfortunately, I didn't study the log detail at the time and I'm uncertain of how to retrieve those logs from two days ago for the ACME activities.
Can anyone confirm that macOS 26 should be storing ACME-retrieved MDM profile-based certificates in the System Keychain? If they should be there, what can possibly go wrong? The most obvious issue I can see is that the ACME server has requested the certificate with two CN's, which comes from the MDM profile asking for the subject against CN and the OID (2.5.4.3). Both CN's are identical.
I'm surprised the profile installed if something is wrong. At first, I assumed Apple had decided to stop installing the certificates into the System Keychain.