It is rather difficult to calculate exactly the score from [SEDE](https://meta.mathoverflow.net/tags/data-explorer/info), 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](https://data.stackexchange.com/mathoverflow/query/1470017/deleted-accounts-above-the-given-score-and-number-of-posts?minscore=500&minposts=50). Notice that you can change the parameters minscore and minposts, you can even [set them both to zero](https://data.stackexchange.com/mathoverflow/query/1470017/deleted-accounts-above-the-given-score-and-number-of-posts?minscore=0&minposts=0).

You can make a similar query which lists both existing and deleted users: [Users above the given score and number of posts](https://data.stackexchange.com/mathoverflow/query/1470018/users-above-the-given-score-and-number-of-posts?minscore=500&minposts=50). (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](https://meta.mathoverflow.net/q/3748). 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](https://meta.mathoverflow.net/q/4426).)