Since the last patch my sims take ages to do certain interactions the most annoying ones are going to toilet and sitting for up to an hour before washing hands OR eating then sitting for ages be...
Yeah it has been an issue since the release of the Sims 4. I'm still waiting for a fix for it. Sims tend to reset themselves a lot too while doing interactions which causes the lag too because it was the fast workaround to routing issues the game was and is still having.