If I were to have the court legally provide a guardian for my father, is there any legal statute that could still allow my input?

Are you unable or unwilling to be the guardian?

Not to my knowledge, I have served as a guardian several times and I had no responsibility to keep family members in the loop, although in several occasions I have. If it is a state appointed guardian, I would say that you will definitely have no input and in most cases not kept informed. State appointed guardians normally have more than one patient on their hands.

The court appointed guardian has no legal obligation to even keep you informed much less accept your input.

i have heard of cases where the family wasn’t even told where the patient was moved to, nor any contact at all.

My guess is no, you couldn’t ‘share power’ - the whole point of the guardianship is to have the power and responsibility. You might find a guardian who would be willing to discuss things with you. Perhaps talk to the court about that.