Microsoft Defender (for Business) not showing onboarded device via Intune

I am having some real fun with Devices not being shown in Microsoft Defender (for Business) after following the necessary instructions provided by Microsoft. Devices are not showing in the Microsoft Defender portal.

I have used the local onboarding scripting method and gone directly through Intune. Would there be a conflict running the two?

The account being used to perform these tasks is a Global Admin (even with Security Administrator rights).

In respect of Intune, the Connection service between Intune and Defender for Endpoint (EDR) is fine.

I have used a preconfigured EDR policy option to onboard the device, and I have checked the registry key HKLM\SOFTWARE\Policies\Microsoft\Windows Advanced Threat Protection, which states an OnboardingInfo value, indicating that a device has been onboarded to Microsoft Defender for Endpoint.

I do have an issue relating to Default Device Compliance Policy - Has a compliance policy assigned and a policy issue for 'create local admin user account', but Intune is saying the device is compliant.

Would these issues cause an issue, and what else should I check for?