Unity Hololens + Vuforia cannot run build for vs2019

All of a sudden I am unable to get my build to run form Visual Studio to the Hololens.

What I did:
- Made a lot of changes ie deleting a lot game objects in the main scene, deleting azure spatial anchors plugin folders and files (not needed anymore) and setting up Vuforia and image target and importing the samples.

Previously it gave me the message "UnityPlayer_UAP_x86_release_il2cpp.pdb not loaded" which I do not understand because this file is present in this folder:
<UNITY_INSTALL_DIR>\Editor\Data\PlaybackEngines\MetroSupport\Players\UAP\il2cpp\x86\release

Now it just gives me the message
"Source Not Available"
Exception thrown at 0x10EAE0A0 (UnityPlayer.dll) in Holosuite Arena.exe: 0xC0000005: Access violation reading location 0x0000000C.
Exception thrown from: UnityPlayer.dll

I did some clicking and now suddenly it appears to remember some settings somewhere, but I have absolutely no idea what is going on...

So far I have a tried:
- Restarting, removing my /builds folder and making a new /builds2 folder
- Various fixes from here https://stackoverflow.com/questions/5309722/a-matching-symbol-file-was-not-found-in-this-folder
- Building in debug/release both in unity and in Visual Studio
- Copy all kinds of project settings from another Hololens project that we have that uses Vuforia

I was planning to create a whole new develop2 branch and completely start from scratch importing MRTK and Vuforia and setting up our image target because we don't have that much in the project right now but I have no garuantee that this would fix them problem....