This is, unfortunately, a problem that many tech companies have made worse and more accessible as they have removed friction from these systems.
Most folks will remember the 2019 temination of lootbox key trading for CS:GO on Steam.
https://www.bbc.com/news/technology-50262447
https://www.gamesindustry.biz/research-identifies-suspicious...
https://www.sciencedirect.com/science/article/pii/S266628172...
I'm not sure what good ways there are to manage this generally, other than limiting the size or types of financial transactions that can occur within a system.