That's a good point re: adding a damage rider at 6th level. Something like, "the first unarmed strike you hit on your turn you can add radiant/necrotic damage equal to half your monk level" or similar.

I do like the scaling cantrip for this build - I think it gives a nice option depending on the scenario, but that it isn't just an auto-pick. Depending on your attack modifier, vs your spell save DC, vs your evaluation of the opponent's save modifier, whether you're hoping to trigger a stunning strike, etc, etc, it adds more options without clearly indicating "option X is always the best one".

Thanks again for your comments!