It is rather difficult to calculate exactly the score from SEDE, but total score (i.e., sum of the scores of all posts) can serve as a reasonable proxy.
Here is a query which looks at such users: Deleted accounts above the given score and number of posts. Notice that you can change the parameters minscore and minposts, you can even set them both to zero.
You can make a similar query which lists both existing and deleted users: Users above the given score and number of posts. (As you have already mentioned, once you have userid, you can find more about that user, such as the list of their posts: Is there a way to check all questions/answers posted from a deleted account. I will add that sometimes you might be able to find also a username that the user had before the deletion - the methods mentioned here work also for deleted users: Recognizing identifiable users changing user names.)