I don't think hackers and criminals use these exchanges. Both exchanges can freeze funds at any time and require KYC as well as the origin of the coins. Why would anyone take the risk, especially those who are aware that their coins did not come in a legal way?
We are talking about hackers who know what they are doing, not random beginners. Right?
Additionally, by using timing analysis, it might be possible to match transactions, especially if the amounts are rounded or specific to certain blockchains (e.g., a specific amount of TRX received on Tron that equals 1 ETH). Unlike Tornado Cash, there's no possibility of delaying transactions with these platforms, which could make timing analysis more effective.
To me, this sounds like one of the competent authorities is trying to do an investigation, so now you are stuck and asking for help. (I have reason to doubt that you are targeting Fixedfloat and Changenow here)
What you are proposing will not confirm with great certainty the connection of certain transactions. It's an algorithm that will base its conclusions on assumptions.
Another platform that will charge for marking coins as "tainted". Super.