DT4 - Add 1st class support for Python in DEVONthink

Perhaps this

Is interesting for you. Last time I looked, it was a Python wrapper for JXA. I don’t know how much of the DT scripting API it supports.

Alternatively, you might want to search for OSA support in Python.

But I believe it’s highly unlikely that DT will get a native Python API anytime soon. Much less an integrated Python interpreter.
Just may personal opinion, of course.