I have a Co-op Adv 2.3 bike. It came with FSA Gossamer Pro 172.5mm crankset with FSA 40T chainring. I've been blessed with short legs (5'10" height with measured 30.8" inseam) so I'm thinking of replacing the combo with Shimano GRX RX810 170mm crankset with 42T chainring. Shorter cranks for my legs, and bigger chainring to help with some extra speed on the road.

First question - will the 2.5mm make any difference, and will going from 40T to 42T be felt? If 2.5mm is not enough, I can instead to 165mm FSA. Assuming I can use the 42T Shimano chainring with it?