For onchain payments, you have BitEscrow by @Tristan (see #541419). For LN payments, you have HOLD invoices, like PlebeianMarket, Robosats are using. You could use Plebeian Market for building your own shop stall inside the platform or build your own nostr market using LNbits (see my guide here).

As others says here, reputation is the most important. All the rest is fixable.