Delete the game page right? Not the game file? I've always deleted the game file first. It has never affected the rating.
Yes. I am talking about the project page. There is two kinds of deleting and both are not good. The first is deletion and creating a new project with same url. That one gets a new id. The second is as the first, but you do not delete, but make it unavailable and create a new url. Also gives a new id, but breaks bookmarks and links as well. If you see version numbering in url, that is often an indicator that the dev engages in this activity.
It gets even more awful, if there is payment active, since itch and the dev are supposed to keep the files available.