Why do all my devices have hidden MDM on them?

I have been of the suspicion for some time that my iPhone 12 Pro Max, my MBP & my ipad have some type of unauthorised MDM on all of them. I have queried this on a few instances with Apple Support staff both via the support app chat as well as in store.

My questions and concerns at all times were brushed off and now I have proof of the above. I am extremely annoyed and am now posing a “Please Explain” to Apple.

None of my devices have been purchased by any business or any other individual other than myself so this should NOT be a practise.

Please explain Apple!