I have 3 pieces to make this work -- brifter, FD, and the crankset -- in 2x10 setup.
From this post -- Compatibility of Tiagra 4700 shifter with MTB front derailleur -- I gather I can match Tiagra 4700 brifter with Shimano MTB FD, like Deore. Ok, so next in line...
Will Shimano Deore FD work with SRAM Boost GX-1000 2x10 crankset: https://www.sram.com/en/sram/models/fc-gx-1002-a1?
My main focus here is on the putting/shifting FD cage over given chainring correctly, so there would be no rub or other shifting problems. But I would also be grateful for comment how far I can stretch official cage capacity (in case of my current 3x9 I managed to use 20T without any problems).
I would like to focus on compatibility and not get involved in "why do you need..." discussion but those side-questions are inevitable ;-). So in short -- I need 22T (with possibility of 20T) in front with 170mm arm (or better 165mm), and I only found this particular crankset. Shimano cranksets starts from 24T and only with 175mm arm, so far from my requirements.