Worth Getting Third Letter of Rec?

So I would’ve got a letter of rec from my engineering teacher (who I had sophomore and junior year) but it is not a core class and most colleges I’m applying to require 2 letters of rec from core classes. If I’m not applying to engineering, is it worth getting one from him since he thinks very highly of me and knows me well? Or will colleges view it as being unconfident and a waste of their time.

A 3rd rec is meant to be a rec from a person that can show a side of you outside a classroom setting. A 3rd rec that mirrors the 2 teacher recs about how wonderful you were in class is wasting AO’s time.

Okay, thanks! That’s what I thought. Just making sure.