when I am modelling complex objects (>1mill) blender usually slows down on undo (sometimes it takes like 5-10 seconds to undo). So the question is am I doing something wrong? Or I just have to learn some techniqes to optimize the scene/workflow?
Blender 2.8 is slow when it comes to undo, and I believe it’s something they’re aware of, and looking to improve. Just out of interest, what is it that you’re modelling?
kinda “organic hardsurface” things
wait, versions like 2.79 or later don’t have these issues?
They often have faster undo speed on versions before 2.8, yes.
It’s not your fault as @Magnavis had said earlier, but you can somehow “fix it” until they a permanent fix is released. Disable all modifiers, and hide the objects you are not working on. You can even try hiding the parts that you are not working on of the active object.