No need for sysdiagnose. Armed with the understanding that this should work, I caught my mistake (I was working on both the provider and consumer side). My implementation of shouldAcceptNewConnection was missing a call to resume. So it was a one line fix. The documentation's use of terms like "your app" and "host app" left me unsure who could consume the service. Thank you for clarifying.

Same behavior persists on iOS 18.5, Beta 2 as well.

Fixed in 18.5 beta 4