i think the client and the relay should be developed as an integrated unit, then the features are going to work reliably, and it lets you shrink the feature set targets down so they get implemented systematically
also, for business use case, good interop is basically essential between clients and relays
there is a definitely discord between the "universal social network protocol" stream of development that gives you the outbox model, and the business use case of isolated subnetworks that don't get contaminated with the general open network