I predominantly use Bisq and LocalCryptos to trade between fiat, BTC, and XMR. I don't use any other altcoins, but I understand there are various instant exchangers and decentralized exchanges which cater to BTC/altcoin swaps without requiring you to deposit your coins to their platform and therefore no issues regarding taint. There's also RoboSats for Lightning trades, although I haven't used it myself it. Try here for other suggestions: https://kycnot.me/