The parts of the CSOM for updating Taxonomy fields are really cumbersome. I mean, look at this code, nicely provided by Vadim Gremyshev (@vgrem). To set a value in a taxonomy field we have to assemble a text representation, and adding a “fake” lookup id. What is needed is a wrapper for handling Taxonomy fields. SPMeta2 and PnP don’t seem to have it yet. Another issue that I have struggled with today was the missing Microsoft.