Why is it so hard to get a device in Intune!!!!

I have devices on my network all around the world , we have some devices that are still AAD not all hybrid joined.  

I want to force to be add to Intune.  There is so much docs, with examples, that dont work.  Here is the scenerio, laptop that is in Azure or connects to Network via VPN.   How do I force it to be in Intune, GPOs are setup , everything is correctly setup.   But we still have issues, from laptops are seen in azure but cant managed,etc .  Is there way to force a laptop to be connected and access intune.   e.g Powershell, etc.