It's a tough situation, but perhaps Bitcoin could implement some kind of tracking system to prevent tainted coins from being used in transactions. This could help protect both buyers and sellers
"Taint" doesn't exist in the blockchain, it's better to leave your UTXOs alone. But if you truly want to make sure that you don't have "tainted" outputs, then try letting them pass through Wasabi Wallet's centralized coordinator. nopara73, Wasabi's developer, works with Chainalysis to "track" tainted outputs.