All the things you describe are 100% normal for a bengal. They don't calm down after being "fixed", in fact, when you first bring them home from their operation they are often even wilder (because of some interaction with the anesthesia) believe it or not.
Bengals do calm down quite a bit when they get older though, but you are years away from that
As far as cables go, I "cured" my cats of desiring to bite cables by coating the cables with bitter yuck.
Scolding a cat is not going to get them to stop playing inappropriately. You need to acknowledge that he has a great need to play, and help him fulfill that need in ways that are appropriate to both of you, and highly desirable to him.