I decided to give this a shot this morning and it actually worked!
I'm not sure who fixed it but it installed from in-game just when I had basically given up on it entirely.

I have tried using a browser and it still doesn't give a PS5 option. I keep going into storage and deleting the PS4 version repeatedly. At least I know that is the problem that is occurring. All the other expansion/add-ons installed for PS5 also install a ps4 version, which is why the file size can...

I have tried using a browser and it still doesn't give a PS5 option. I keep going into storage and deleting the PS4 version repeatedly. At least I know that is the problem that is occurring.

I'm getting the same issue on PS5. I've:
Restored licenses
uninstalled and reinstalled
swapped to internal storage
Cleared PS5 cache
Repaired database
Tried installing from the app
Waited 72 hours
And every other possible solution suggested anywhere.
Apparently it is a Giants issue