I think the solution to that is to simply find ways to lock you out of those functions later in the game. Much like World Tension gives you new abilities as it goes up, it also takes some away, so the players can concentrate on fighting. "Sorry, we can't sell you [STATE/RESOURCE RIGHT], we need everything we can get [while we're fighting the Axis/in case we need to fight the Axis]!"Peace treaties are a difficult one. I know a lot of people would like to see this, but in practice it runs counter to HoI's design philosophy of "crescendo to war" in most cases. I don't think that means similar things can't be done, but the ability to simply peace out when you've had enough is unlikely to be seen.
Acquiring land peacefully is something that for similar reasons is unlikely to exist in a systemic form. There are narrative beats where we might want to make this happen, and you'll see it happening in focus trees because they also contain an arena to explain the what/why and the fallout from a narrative perspective.
There are other options, like National Spirits: German Reich's Bitter Loser will make it so they'll never accept a peace treaty, no matter how badly they're losing, or things like being at war with a country that has X number of factories/deployed troops.
If you want players to concentrate on the war when it goes into full swing, that's perfectly fine, this IS a game about World War II, and the war itself should be the main focus. But the more you can do in the time leading up to the war, the more possibilities can play out during the war.
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