AnotherGame is a mod for ToE 3.1.

As I understand it, players should be "rolling in wealth" to afford mine upgrades costing 7500. My suggestion, specifically for the IRMG, is to either increase the cost of building a castle (including the Capitol branch) or reduce the reward from treasure chests (and lower the price of mine upgrades).

I understand that you want to see the upgrade as an alternative to a castle, but the upgrade is more of a complement than an alternative. At least because not all mines have an alternative. And with this version, there won't be any "sacrifice." A rare, valuable resource should be rare, and as a result of the cheap upgrade, we will get all resources being equal, which already resembles a "six" (referring to a balanced, but uninteresting, state). Again, you are trying to solve the problem through "nerfing" (from the word "pawn"). Well, yes, it's easier to balance the game with that logic, but why do it when diversity is lost? Selling resources on the market is expensive for a reason – to prevent resources from being equalized.

Normally, in a situation where I lack a couple of resources, at the right moment, I will exchange them on the market, and gold will be my last resort. Therefore, in my opinion, mine development is inferior to the market.

That's why I suggested switching the upgrade to other resources so that it doesn't affect the amount of meat available for purchase. Although, to get through, sometimes only 3-4 types of creatures are bought, which is enough.