It should be backwards compatible with the PS5 from what I know. Like if it's registered to your account, then you just need the digital download without the disc. I did that with my PC. Bought disc at launch of the game (Since digital downloads were halted for a while), and when I got my new desktop last year I could just download everything from ARR until 5.X without the disc.

I don't know if they'll actually make a PS5 disc though.