To be honest, yes you did donk off a stack. Shoving preflop is completely standard, 3betting to snap off is fine too if you have an image of 3betting a lot and he might 4bet pile some hands which he would fold to a shove.

Don't mind checking back the flop since he pretty much doesn't fold any better hands or call with any worse. Also don't mind betting just to make the hand easier to play and avoid a weird turn spot. I don't really understand the turn bet since you're representing a hand that had some showdown value on the flop but improved on the turn, and there just aren't really any of those hands in your range. There's very few 5x hands in your range and you would probably bet those hands on the flop anyway. You can't have overpairs once you check the flop, and valuebetting a 6x hand would be thin anyway since you rarely get called by worse.

So basically your turn bet is a bluff that doesn't rep anything, and your sizing is so big that you felt committed to calling off once you bet, even though he basically doesn't have any hands in his check/jam range that you beat. If he was going to bluff that turn card he would probably have led out, and he can't expect you to bet 4k and fold to 11k very often, so IMO when he check/jams here vs that sizing he pretty much always has 5x.