To resolve the certificate mismatch error, you should reissue the client certificate with client authentication enabled. According to 1, when you use Azure certificate for authentication type on point-to-site VPN connections, you need to ensure that your client certificates have client authentication as one of their enhanced key usage attributes. Otherwise, you will receive a certificate mismatch error when connecting by using a VPN client.

The proposed solution to use a global administrator account that is not federated to configure Azure AD Connect does not directly address the error message "Error getting auth token" described in the scenario
, so it is unlikely to solve the issue.
To resolve this issue, you should verify that the Azure AD Connect server can authenticate to the Azure AD tenant using valid credentials. If authentication is successful, then you can investigate other possible causes such as network connectivity problems, misconfigured firewall rules, expired certificates, etc.
Therefore, the correct answer remains option B, "No".
Reference:
https://docs.microsoft.com/en-us/azure/active-directory/hybrid/tshoot-connect-authentication
https://docs.microsoft.com/en-us/azure/active-directory/hybrid/tshoot-connect-password-writeback