Would it be possible to add downloadable Apple config profiles (.mobileconfig) to the web UI, so Mail and Cal/CardDAV get set up in one go on macOS/iOS?
Right now every Apple device has to be configured by hand - hostname, ports, DAV paths, credentials, all separately. For a single power user that’s fine, but rolling this out to business customers means walking non-technical people through it on every new device, which gets old fast.
mailcow already does this really nicely: you log into the UI, download a .mobileconfig, open it on the device, done. They even have a variant that embeds an app password so nothing has to be typed at all (with a warning not to share the file, since it then grants account access). Apple macOS / iOS - mailcow: dockerized documentation
Since Stalwart already serves mail, contacts and calendars from one place, it has everything needed to build such a profile. Would be a big help for Apple-heavy environments.