With your planned budget, it sounds like the 7D m2 would be good, especially since you plan to photograph birds (I assume it is birds, considering you have a 150-600). The 80D is also priced similarly - you will need to compare the specs and features.
I have used the 7D m2 for birds at times when I can't afford to miss the shot (including in poor light), and yes, it delivers brilliantly.