Updosing whilst keeping the yield the same will increase strength and body, but will decrease your extraction and make your shots taste more acidic/sour.
Grinding finer will increase the run time, which will make your shots more extracted which will increase the sweetness/bitterness of the shot, and will also slightly increase the body.
Grinding finer is always the better option as it’s good practice to keep your dose locked at one weight for consistencies sake, try playing around with your yield to change the extraction/body of your espressos, there’s some good reading material on this on the archives section of barista hustle!