Re: If I get bf2042 on xbox 1 can I play 128 servers once I move to the series x?

@Crilp663 Yes.  You will if you purchase the Gold or Ultimate Editions of Battlefield 2042.

The Gold and Ultimate Editions include the “Cross-Gen” bundle for exactly that purpose. It is essentially both versions of the game for the older gen and next gen consoles in a single purchase.

Also, the cross-progression feature will let you keep your in-game rank, unlocks, skins, etc. whenever you do decide to upgrade.