All are ok and natual??
I wish I could be more help to you.
I wish I could be more helpful to you.
I wish I could help more to you.

Question

Answer

I wish I could help more to you. X ------> I wish I could help you more.
I wish I could help more.
I wish I could be more help.

Answer

Your first and second sentences are ok and natural.  The third isn't.  You could say, "I wish I could help you more."  Another way involves the word "of":  "I wish I could be of more help to you."  "to be of help (to someone)" is fairly common, and is perfectly natural.

Evden çıkmadan dil öğrenme fırsatını kaçırmayın. Deneyimli dil eğitmenlerimizden oluşan seçkimize göz atın ve ilk dersinize şimdi kaydolun!