Why can't i create a GPO to install a .msi to clients? - deployment

Question

(I am using a german Windows Server 2019, so bear with me. I try to translate everything to recognizable english ui equivalents)
The goal is to create a GPO to install a .msi file to client computers. Everytime I try to create the GPO, it says
Add operation failed. Unable to extract deployment information from the package. Run validation on the package to ensure that the package is correct.
The Windows Event Log outputs a warning and then an error(translated by me).
Warning:
Warning: Event 119, Software Installation
While reading the msi file \\dc1\gpo\Install\AnyDesk_Client_v2.msi, an unexpected error occured. The error is not severe enough to cancel the operation. The following error occured: The operation was completed successfully
Original german text:
Beim Lesen der MSI-Datei \\dc1\gpo\Install\AnyDesk_Client_v2.msi ist ein unerwarteter Fehler aufgetreten. Der Fehler ist nicht schwerwiegend genug, um den Vorgang abzubrechen. Folgender Fehler ist aufgetreten: Der Vorgang wurde erfolgreich beendet.
Error:
Error: Event 103, Software Installation
The Software Installation could not deliver/prepare the package AnyDesk_Client_v2.msi. The following error occured: The directory name is invalid
Original german text:
Die Softwareinstallation konnte das Paket AnyDesk_Client_v2.msi nicht bereitstellen. Folgender Fehler ist aufgetreten: Der Verzeichnisname ist ungültig.
What I tried:
Using another msi. Used the standard Anydesk.msi (so no "_" in the filename). I tried the Teams x64 .msi from MS Teams MSI Download. I tried a Futuremark_SystemInfo.msi I had
lying around.
I put all the files in \dc1\NETLOGON and tried again. I put all the files in \dc1\SYSVOL and tried again. I checked that authenticated users had access to the share. I logged on directly on the Domain Controller as Domain Admin via RDP. I logged directly on the Domain Controller via VMRC (it's a virtual environment). I checked if I can access the shares I put the .msi's in (I can). I got a tip that says
Go to Default Domain Controllers Policy
Expand Computer Configuration\Windows Settings\Administrative Templates\System\Netlogon
Change the Netlogon and Sysvol Compatibility to enabled (2 seperate settings)
This does not work because there is no Computer Configuration\Windows Settings\Administrative Templates - it is Computer Configuration\Administrative Templates. But there is no setting to enable NETLOGON/SYSVOL Compatibility underComputer Configuration\Administrative Templates. I assume this is a tip relating to an older Windows Server version.