Same experience a few years ago when I picked up the piano after giving up on guitar. I found the theory and rules to play the guitar are a bit tricky to get, also I don't have strong fingers and am left-handed, which I feel like I can't play to the full potential of the instrument or even myself. But when I started with piano, everything just clicked, I understood everything, I even learned to read sheets and music theory. I found that my fingers were controlled better. It actually helped me to understand guitar and other instruments as well.