I just upgraded Illustrator to the latest update (2021) and i'm encountering some issues when I am copying/pasting in the same artwork. I work on high resolution images and when i copy one image or complex art the software freeze and seems to load the data... it never happened to me before. The only times it occured it was when i was trying to copy/paste illustrator to photoshop. Otherwise it was fast in only illustrator.
It can slow down quite a lot my work flow when I'm slicing my high resolution art.