I've seen a complaint about an instant exchange: the deposit was frozen by the third-party exchange they used "because of taint". They claimed the user needed to go through KYC, and after that the money was magically okay again. It turned out they used Binance, and the funds were added to Binance's large wallet. Does that mean the "taint" is magically gone? Does it mean the exchange sells "tainted Bitcoins"? Or does it means there was no taint in the first place? My money is on the last scenario.
Unfortunately there's no way to know which exchanges are the ones making an issue about taint because they'll throw KYC out at you for a variety of reasons and taint is just one of the excuses they can make.
What if there was some feature built into Bitcoin Core's wallet, and other wallets, that periodically "rotated" your funds to newly generated addresses over a 24hour period. And then, whenever you need to make a transaction, RBF can be used to override the previous rotation transaction.
Bitcoin Core is especially suitable for this as they pre-generate a thousand private keys and associated addresses for a given wallet.