We recently evaluated several remote learning options to improve reading fluency and vocabulary. From my observation individual sessions generally work better than automated apps because an instructor can correct pronunciation in real time. If you want to study the details of structured reading programs and lesson formats, you can inspect https://brighterly.com/online-reading-tutor/ to see how their curriculum is organized. In our case having custom interactive materials helped keep attention focused without overwhelming the child. Progress depends heavily on consistent schedule and teacher style, so testing a trial class first is usually a sensible move before making any long commitment.