Editing P. Styles when you have Views open has always been slow, but in v8.1.27 it seems even slower
I only have 2 very simple Views open (maybe 15-20 components all up, half of them are flex containers, the others are labels, but it takes 30s to save... The last I heard, the CSS styling has to be reapplied to the opened Views, but that efforts would be made to make this a background process instead of a foreground hold-up.
This is all I have open:
If only the top "Replenishment" is open, it takes 13s - still absurdly long