Turn OFF Windows Defender via group policy (Microsoft Defender)

Open group policy editor
Create a new policy called whatever you wish, edit the policy

Navigate to Computer Configuration\Administrative Templates\Windows Components\Microsoft Defender Antivirus

Edit "Turn off defender antivirus" and set it to enabled

Then link the policy to whatever OU's you need to

Check your services after a reboot, look for Windows Defender,
They should be disabled.