This tiny article explains how to remove windows defender using PowerShell on a windows server 2019 ( works on windows server 2012 and 2016). Windows defender antivirus comes preinstalled with all the windows server versions. In windows server 2019 it has built in ransomware protection that work pretty good in realtime.
Most times windows defender make conflicts with other third party antivirus solutions. In that case you need to remove windows defender. Or you cannot proceed without uninstalling windows defender.
Remove Windows Defender using PowerShell
Run the powershell as administrator and run the below command to uninstall windows defender antivirus
PS C:\Users\Administrator> Uninstall-WindowsFeature Windows-Defender
PS C:\Users\Administrator> Restart-Computer
Above command will restart the server to complete the defender removal process.