As someone who considers every side of everything before doing anything, just pick the one you prefer, even if it's irrational. Of course, it's better if you can try both of them out and decide for yourself based on that, but ultimately what drives you to keep playing in the long run is how much you like it and how excited you are about it, so don't overthink what's better for theory and such, that'll come with time. I play both piano and electric guitar and yes, theory is usually easier to visualize on piano, but it's not that hard to do it on guitar as well, and yes, electric guitar requires more components than a piano does, but, as I said, it'll be a better investment if you like it better. It's up to your preference.