Explanation
In the Microsoft Intune admin center, you can assign apps to users or devices. Users can be assigned to apps by using user groups or individual user accounts. Devices can be assigned to apps by using device groups. In this scenario, the objects shown in the table are as follows:
Admin1 is an individual user account that belongs to the Global administrators role group.
Group1 is a user group that contains 100 users.
Group2 is a device group that contains 50 devices.
Group3 is a user group that contains 200 users.
Group4 is a device group that contains 150 devices.
Since App1 is a Microsoft 365 Apps app, it can only be assigned to users, not devices. Therefore, Group2 and Group4 are not valid objects for app assignment. Admin1 is also not a valid object for app assignment, because individual user accounts can only be used for testing purposes, not for production deployment.
Therefore, the only valid objects for app assignment are Group1 and Group3, which are user groups.

Explanation
To ensure that Profile1 applies to Device1 only, you need to modify the Applicability Rules in Profile1. You can use applicability rules to filter which devices receive a profile based on criteria such as device model, manufacturer, or operating system version. You can create an applicability rule that matches Device1's properties and excludes Device2's properties. References:
https://docs.microsoft.com/en-us/mem/intune/configuration/device-profile-assign#applicability-rules

Explanation
References:
https://docs.microsoft.com/en-us/microsoft-store/distribute-apps-from-your-private-store Enable the users in the MKG department to use App1.
The private store is a feature in Microsoft Store for Business and Education that organizations receive during the signup process. When admins add apps to the private store, all employees in the organization can view and download the apps. Your private store is available as a tab in Microsoft Store app, and is usually named for your company or organization. Only apps with online licenses can be added to the private store.
Reference:
https://docs.microsoft.com/en-us/microsoft-store/distribute-apps-from-your-private-store