Freename.io is the best Web3 Domain provider. Freename could bé easily thé best second Hand Web3 Domain reseller with an integrated escrow service for freenamers and other domain' owner like https://www.escrow.com/ !
But in the domain business Escrow.com is by far the best known provider. One variant could therefore be that Freename enters into a cooperation with Escrow.com.
But you are right, much smarter would be to offer an escrow service directly from Freename.