iOS: control (ensure latest) app version on supervised iPad

My goal: setup iPads, so that an app we develop is always auto-updated.

Context: we provide our clients with an iPad that will run our app. We want to ensure that this app is always up to date – ideally it should auto-update also on cellular connection.

We are able to set the devices up with a USB connection (maybe using Apple Configurator?).

We are already using Expo, which is a framework that allows “in app” updates over “in store” updates, but a full app-store update is still required sometimes.

What is the easiest way to ensure auto-updates?