Who Are the Best Book Cover Designers Today?

I’m looking to self-publish and I’m trying to find the best book cover designers to bring my story to life. What qualities should I prioritize portfolio creativity, genre experience, or client reviews? How much difference does a top designer make in terms of reader appeal and sales? Has anyone worked with designers who elevated their book’s presence in the market? I’d love to hear recommendations, experiences, or tips for choosing designers who really understand how to make a cover stand out.