Unless the sequel is using way better tech and requires a new engine or massive engine tweaks, a sequel that comes shortly after the original release could be done better, faster and cheaper as an expansion pack.
Other than EUIV though, whose expansions are a money grab way to make the game cost 150 bucks, I haven’t ever played DLC I can think of.
Well there ya go. Paradox DLC is just bullshit. Most of them just add like 1-2 units or characters or factions which mostly boil down to an aesthetic change. Most big games get real additions via DLC that can add up to 50% more game.