Can I play the game on the PlayStation 5 Digital Edition if I own the disc copy on PlayStation 4?
No. With backwards compatibility, you are able to insert the physical PlayStation 4 disc into the PlayStation 5 and play it. This also means you’ll be able to download the game if you purchase it from the PlayStation Store digitally (assuming you are using the same account).
However, you won’t be able to play the game on the PlayStation 5 Digital Edition if you own the game physically as it doesn’t have a disc drive.