Configuring Microsoft Defender Antivirus for non-persistent VDI machines

Daniel-San  funnily enough, I have just rebuilt a 1909 image and tried to configure defender (with all the pre-existing infrastructure in place..) and I see the same problem you are having  8007005 error in the event log and VM's not updating. I'm comparing my working build to this one, can't find anything different and a few things that I've checked that I hadn't shared earlier-

-March OS patching for windows - I've not explored if this could have broken something?

- This article has a few other bits to check in your registry: https://docs.microsoft.com/en-us/microsoft-365/security/defender-endpoint/troubleshoot-onboarding?view=o365-worldwide#ensure-that-microsoft-defender-antivirus-is-not-disabled-by-a-policy 

- I've enabled SMB 1.0 via windows features - in our environment we have a number of v old file servers - I don't know if our definitions are on a box running smb 1.0...

Let me know how you get on as I suspect I have the same problem as you at this point?