Just watched it and while cap+lightning, cap's return and some other things require a bit of "flexible logic" I'm willing to forgive it all for one simple reason.
As soon as the huge fight started I was reminded of a quote:
"Behold! The awesome fires of god. The limitless power of pure creation itself", my master would say. "Look carefully! Observe how it is used for the same purpose a man might use an especially sharp rock."
The whole thing was some straight up medieval shit, just people whacking each other with fists, space swords and everything in between. No one ever brings artillery to these fights. What are we, barbarians?
Well turns out that even though his execution was lacking this time, Thanos' plans are solid as always. He did bring artillery.
Be smart, be like Thanos. Bring artillery to a fist fight.
I mean I don't watch these films for hard sci-fi, I watch them for entertainment. Did it entertain, did it do what it should, was it a worthy finale? Yes it was.