Sorry but, do you know exactly what trustless means?

This concept applies to custody, not to fiat-to-crypto exchanges. Because a fiat-to-crypto exchange is an on/off ramp into/outside crypto. And as fiat cannot be held in a trustless way, the most "trustless" way to make a swap without the exchange holding the fiat amount is by using an escrow system. If the escrow system can only be moved to party A or party B during a trade-dispute, then it's the most trustless thing you can get, my friend.

PS: Your 2nd link seems to suggest that you're saying "DEXes are better than p2p exchanges!", well, DEXes don't have fiat-to-crypto pairs, only crypto-to-crypto. Nice try.