Android doesn’t currently have automatic sync like iOS/iCloud.
Choose a “primary” device.
If adding content or editing using a different device, share it with yourself (email,DropBox,Drive,etc.)
Open the new content with your “primary” device.
Regularly, make a backup of your “primary” and share it with yourself as above.
Open iRp on a different device, clear all content (songs and playlists), import the primary backup. = sync.

)BOB