You can manage apps using app protection policies on company-owned devices that are enrolled in Microsoft Intune (Device1 and Device2).
Personal-owned devices that are not enrolled in Intune (Device3) may have limitations in terms of the app management capabilities you can apply.
You can manage the apps on this device using app protection policies. Since it's a company-owned device and enrolled in Intune, you have more control over the device and can apply policies to protect corporate data.
You can also manage the apps on this device using app protection policies. Similar to Device1, company-owned devices enrolled in Intune allow for more control over app management and protection.