Piano or Guitar?Watch
I enjoy guitar more and there would be a lot of learning involved but if I play piano and prep myself, I could up a grade on ABRSM.
Guitar is easier to idly practice. Piano is something you need to actually sit down at a specific spot to do, whereas I can just do exercises on the guitar while watching TV
Doing an instrument just to get grades isn’t the point of them- grades are one way to gradually learn an instrument and get better. It’ll be more fulfilling to learn an instrument because you want to and maybe pick up a couple grades along the way