The fact that you are getting steady interviews speaks for itself that you have the design chops and experience. I think people don't know how to interview design candidates well as is, removing the physical cues you get from an in-person interview makes it even harder to assess a designer. Also, it could just be companies are flying by the seat of their pants and a lot have reduced workforce with this second wave of infections.
High probability it's not you, it's them and their broken process during covid-19. Keep your design skills sharp and keep building your portfolio and use this time to work on concepts that you are passionate about that haven't come up in a 9-5, that will help you until the right opportunity comes along. You got this!