I inquired about this topic and it turns out that there are already different ways to modify the war / peace systems of the game. For one, you can mod the DiplomacyModel. More specifically, you can overwrite the GetScoreOfDeclaringWar and GetScoreOfDeclaringPeace to change how profitable a faction would view it to to declare war or peace. (Here you could adjust how much other ongoing wars or war exhaustion / duration matters.)
Having said that, maybe you are looking to directly adjust the thinking frequency handled in KingdomDecisionProposalBehavior.DailyTick or make other adjustments in this part of the logic. If so, you can remove the native behavior and add your own custom one to replace it.
Cheers for sharing that. I will raise it with the relevant people to see if they are aware of it.
Because players requested it (much like they have in the posts I initially responded to). Outside of the hard truce period, the system works like you describe.