I would really like to see some kind of percentage-based penalty for unscrupulous sellers

In short, as a buyer, I’m currently purchasing certain items from sellers through your platform. After waiting four days for “Steam Protect,” the seller simply goes ahead and cancels the transaction (having received only a trade ban from Steam itself as a penalty), I would like to see a more stable and predictable situation; you have penalties for buyers, but none for sellers (I’m not talking about individual sellers, but we all understand that, as a platform, you’re generally not very interested in such customers), Let’s consider sellers who systematically engage in buying and selling items. I ask you to either hire a professional specialist on an outsourcing basis or bring such a person onto your staff, since both I and many others who use your platform choose it precisely because of prices that are closest to the real market. So, you need someone for this to assess the percentage by which you set the price lower or higher for the buyer or seller, respectively, and based on that percentage, impose a penalty on the seller (again, I’m referring to sellers who systematically use the platform). These funds are then split between the buyer and the platform (the buyer obviously receives at least some compensation from an unscrupulous seller, while you, as an aggregator, earn additional profit thanks to more favorable prices compared to competitors).