Getting into new field after tech career / PhD in STEM, should i start a new degree as undergrad or at postgrad level
I don't see any reason to formally do another undergraduate degree. And you may not even need a credential at a higher level if you already have a doctorate and some publications in your new field.
My perspective is the US, where an undergraduate degree has a lot of things not related to the &quot;major&quot; subject. That is different elsewhere, of course.
But there may be some gaps in your education. If you are at a university, there is little reason why you can't ask a professor in some other field if you can &quot;sit in&quot; on one of their courses. I've done this, actually. The professor even agreed to give me ordinary student feedback (but no posted grade) on the homework assignments and exams. It was all informal and just let me &quot;scratch an itch&quot; in his field.
Once you think you have the knowledge gaps plugged you can, if you need the credential, apply for some higher level degree. You probably need to ask for special treatment in the admissions process, I suppose, but can probably justify it.