I suggested a open wealth ranking before, I know you might not approve it, but is there a chance that we can have a monitoring tool for admins to see the wealth ranking and prevent some player from gaining abnormal amount of money by bug or cheating?

I do not know if this is feasible. The nature of Numismatic Overhaul is item-based. Any wealth could literally be placed beneath your floorboards in chests should you desire, hiding it from any reasonable wealth query

Recently I founded an abnormal number of serverworth in my server (96 Trillion total asset), I want to found out which account has this amount of money, could you please tell me where to look for player’s numismatic account data? Or could you please add a ranking function?

The wealth stored in players' purses is in the players' NBT data under (this might be outdated!) cardinal_components > numismatic-overhaul:currency > Value. For currency stored in item form, check the players' inventories or chests.

Is it possible to search it in all of them but not one by one? Maybe a wealth ranking?

There isn't anything built into Numismatic Overhaul for this (afaik). I described the way to do it manually with an NBT editor.