I've been doing some reading that says scapula wing because of a weak serratus. I've been concentrating on feeling my scapula lie flat in all the movements and thought i was doing things well because all of a sudden my shoulders, lats and traps are firing properly for the first time in my life, but when I looked up exercises to strengthen the serratus I learned that the best exercise is scapular push-ups. Apparently I should feel them firing when my shoulders move forward because they protract the shoulders... but on scapula push-ups I only feel my pecs firing.
Any tips on activating the serratus? Mine is quite dysfunctional and checked out decades ago.