As somebody who was browsing Giant Bomb Dot Com and saw a glimpse of this thumbnail as I was downloading Destiny 2 on PS5, when you select options you can see the Game Version. You can then select and download either the PS5 version or the PS4 one.
Yeah, I saw the option for "Game" or "Game" and thought "What the hell is this", but Options > Game Version is how you can double check that.
Sincerely,
A person who almost downloaded both versions of Destiny
clagnaught's comments