We installed SP 2019 on prem and configured ADFS authentication. After setting up OneDrive with the specific "on prem GPO" for connection the standard windows authentication promt comes up and we cant access the library through OneDrive. Is there a way to force OneDrive to specific ADFS Login Url!?
OneDrive NGSC does not support SAML. You need to use Windows Authentication (NTLM or Kerberos but the NGSC does not support Kerberos on macOS).
Since you have ADFS, instead of using SAML, use a non-claims relying party on ADFS for SharePoint. This will allow you to use Windows authentication (Kerberos Constrained Delegation) instead.