How do (STEM) professors keep up with the latest tech or development in order to publish research?
In short, your premises are wrong.

Professors read papers to learn.
Professors meet with their peers, both at conferences and informally, and learn from them.
Professors do learn from their research students.

These are slow methods of learning, but over many years they add up.
Further, in fast-moving fields of research, nobody &quot;keeps up&quot; in the sense of knowing everything that is going on.  It isn't necessary to know everything that is already known to create new knowledge.