LMAOI saw someone on the X-Men subReddit talking about how (to them) the mainline series ended with Days of Future Past/Logan and Apocalypse/Dark Phoenix is just an unessential mediocre spin-off.
Or, as they brilliantly put it: "Logan was the last episode of Friends. This is the last episode of Joey."
#Rekt'd
If you look at it like that, X-Men had a pretty solid run.
X1 - X2 - X3 - The Wolverine - First Class - Days of Future Past - Deadpool - Logan - Deadpool 2.