I've read a lot about Mengele and he was lots of things but a "doctor" wasn't one of them.  He was an experimenter.  He practiced on live people rather than cadavers.  He was a butcher.  He cut out his own feelings.

https://blog.nomorefakenews.com/2022/08/15/did-dr-mengele-know-he-was-dr-mengele/

We have lots of doctors today just like him.