Ps5 battlefield 2042 standard disc has no ps4 version

So I bought a ps5 disc version and not able to play with ps4 friends, even though it says in game cross generation, though it said it will be limited to 64 players to play against ps4 players. But still can't play with ps4 friends. Ps4 players who have a disc can upgrade to ps5 version, but ps5 disc players can't get a free ps4 version on ps5. Doesn't make sense. I'm done with Battlefield. You can upgrade, but not downgrade to play with friends. if I buy a digital ps5 version, then I shouldn't have to buy a xbox series x version either, since my EA account is linked. It is all bs if you ask me. Like I had to buy fifa 21 on my switch even though I have it on ps4. But if it was on pc, I can go from a good computer, bad computer or super gaming computer and still play the same game paying once. The game should not say cross gen on ps5 if you have to buy the ps4 version and upgrade for the same price as the ps5 version.