History Memes

But sometimes I could get away with sharing technological secrets instead of a tangible gift, which cost me nothing and helped their culture progress toward an innovation that mine had already discovered. Any historical basis to that?

"Technology", both in real life and in CK3, is a very funny thing. Insofar as pre-modern polities did sometimes discuss such matters as we would recognize as belonging to the realm of technology, yes. Any technology 'transfers' would largely have been specialists being sent to train other specialists (smiths, weavers, woodworkers, etc), rather than more abstract exchange like texts or diagrams, or of specific techniques.

Unfortunately, my knowledge of China is rather sparse, so I couldn't definitely say whether the Ming sometimes did that, but I would imagine so.