Even we too have similar kind of issue wherein we don't have a mechanism to relaunch background app which runs continuously in case of crash. We get user consent to run this background app and are using helper app installed via SMLoginItemSetEnabled API to launch background app on subsequent login. But helper app is terminated once it successfully launches background app. So @Eskimo do you mean we can use the helper app to monitor the state of main app and relaunch it whenever crashes. Can we keep the helper app installed via SMLoginItemSetEnabled API running all the time?

Yes our app is sandboxed and ships to Mac App Store. And yes we did check on SMAppService which support macOS 13 & above but to support older macOS we still use SMLoginItemSetEnabled API. But as we checked the problem still exists even with new SMAppService there's no mechanism to relaunch main app in case of crash..Is our assumption right?

Yes your understanding is correct. Helper app it terminated once its launches the background as its job is done. But now we are thinking to keep it running and monitor the background app, relaunch it if crashed. Now our query is can we keep the helper app running all the time?