In the current (as of writing) edition of the G2G mod there is a big issue with inflation, as Upkeep gets impacted by inflation (which I am happy with as a feature and do want it to stay)
This has the unfortunate side effect of causing inflation to start oscillating with increasing amplitude after Dust production & upkeep get above certain values.

As such I was wondering if a new property for both ClassEmpire & ClassMarketplace could be created, DustGlobalUpkeep which would be like DustGlobalProduction but be the sum of all Major’s EmpireMoneyUpkeep instead of NetEmpireMoney. This also has the upside that as it’s just adding a property (not changing any current ones) it would have no effect on vanilla.

From this, we can then use DustGlobalProduction + DustGlobalUpkeep to get DustGlobalGross and that can be done in XML so this does give a lot of advanced options for modding inflation.

With it, (using PARAdoxiBLE's most recent suggestion, See inflation (expected) as the end of their post) inflation oscillations caused from affecting upkeep could be completely stopped.

I would not expect this to be too much work to implement (given that it’s duplicating the effect of DustGlobalProduction but changing the variable it sums to EmpireMoneyUpkeep from NetEmpireMoney)

This code that (I think) would need additions to add DustGlobalUpkeep:

// Token: 0x0200109D RID: 4253
//Sets up the variable
public class OrderUpdateDustInflation : Amplitude.Unity.Game.Orders.Order

//Contains property name strings
public static class SimulationProperties {
   // Token: 0x02001AD8 RID: 6872
   public static class Empire
   …
   // Token: 0x02001AFF RID: 6911
   public static class Marketplace

// Token: 0x02001A6E RID: 6766
public class GameServer : GameInterface … { 
    // Token: 0x0600F87A RID: 63610 RVA: 0x003D3450 File Offset: 0x003D1650
    //Sets the variable by summing the Major Empire’s values
    private bool UpdateDustInflationPreprocessor(OrderUpdateDustInflation order)

Hey CyRob,

I'm not sure I really understood what's needed,

You just want me to add the property DustGlobalUpkeep and keep it up to date?

And with a mod, you could use it to fix the inflation oscillation?

I'll put it on my magic modding post-it but as you know, I cannot guarantee when or if it will actually be done one day.