Hand is played fine imo. 3bet could be bigger but that's nitpicking. Once were 5betting we might as well be shoving. Can't see any reason to flat his 4bet mostly because it's 4nl and we're getting called a lot here.
I dont think its nit picking to size a whole lot better than this. 3 bet size is way to small 5 bet shove is huge you force him to have a hand.