I do believe Mia Goth, Jenna Ortega, and Anya Taylor-Joy are the frontrunners for modern horror Scream Queens.
Obviously, I believe that quality should outweigh quantity by any measurement, but I also find myself wondering whether ones' contribution can be quantitative enough that it substantiates into earning the title of "Scream Queen".
For example, I don't know if I have seen a film from Danielle Harris that I consider to be a truly great film. But, she was in Halloween 4 (which I considered a slightly above-average slasher film), Halloween 5, and both Halloween remakes (for which she admittedly had smaller parts).
She was the main-protagonist for Hatchet 2 and Hatchet 3. Other than that, she has had main-roles / supporting roles in about a dozen or so other indie horror films (largely varying in quality).
She has been in a lot of them, and even if they weren't good movies, I usually found her to be one of the stronger aspects of them.