Defender can be a pain, but generally bypasses are abundant. This page is focused on enumeration not bypasses.
Defender Enumeration with Powershell
Get-MpComputerStatus #See the status of Defender
Get-MpPreference #See current Defender preferences
Add-MpPreference #Change Defender Settings
Get-MpThreat #See threat history for computer
Get-MpThreatCatalog #Show any known threats
Get-MpThreatDetection #Show all history for any detected threats
Remove-MpThreat #Remove an active threat
Remove-MpPreference #Create exclusion and default behavior
Start-MpScan #Start Defender Scan
Update-MpSignature #Signature updates
Set-MpPreference #Configures scans and updates
Processes
tasklist /v
look for:
MsMpEng.exe
MpCmdRun.exe
File System artifacts
download below files
dir "C:\ProgramData\Microsoft\Windows Defender\Support\MPLOG-<Datetime>.log"
dir "C:\ProgramData\Microsoft\Windows Defender\Support\MPDetection-<Datetime>.log"