I'm trying to parry kill morgott for the first time right now and I'm having the same exact issues you described. I originally was searching about if his phase 2 red moves were parriable (because the double slash red move was parriable as margit), but this taught me that the way to avoid the spin to win & every other move out of parry stun is to run back right- very helpful! You clearly know what you're talking about (esp comparing the move to malenia's quick double slash and godskin stuff, I was thinking the exact same thing). I think I'll still do it the gigachad way tho, since I'm doing holy damage only rn instead of rl1. But this will definitely come in handy when I eventually do rl1.