You can adjust which lists are visible on the Home Screen by using the Lists icon in the upper right corner. If you just want to view the files that have been synced to your iPad you can tab the Files icon in the lower nav bar.
For Dolby Vision, there is a small percentage of Dolby Vision files that will not be supported on Apple devices. Disabling the Dolby Vision will allow the video to be played in HDR.
There is also a known limitation with the 9th/10th gen iPad and you can follow this thread for updates in this area.