Some time ago I had a similar idea based on another project, I only kept it as an idea because I'm not a dev and I have no idea how to do it. It would be to use nostr and PLS for rides and deliveries, just as you proposed. Each order would automatically create a contract on PLS between the provider and the user with a default (or otherwise chosen) arbitrator, the contract is sealed with the service amount in sats by the user and a kind of "insurance" amount by the provider. At the end of the ride the contract remains pending objection and a deadline is set; if it is not contested the contract is closed, the payment and the insurance go to the provider and both reputations are recorded as an agreement closed pending written review. In case of dispute the arbitrator is triggered.