My company just started requiring Microsoft Intune Company Portal app to use Teams and Outlook. From a friend in IT infosec at another company said the app can push apps, require certain settings, password requirements, or OSs, and can see a lot of stuff on your phone. I don't think this level of intrusion into my personal phone is warranted or ethical. Be warned. I'm just going to uninstall and suffer the internal political consequences.
If you're hourly, that totally makes sense, but if you're salary then in a lot of places in the world they kind of semi-own your ass and you do have to check messages outside of "work hours" since those technically don't exist for you. Some companies might enforce the standard 8-5, Monday through Friday and encourage only working 40 hours a week (and those are good companies), but legally they don't have to limit it to just that on salary.