Exchange Online Powershell BasicAuthToOAuth not working with WSManConnectionInfo

Our code currently uses WSManConnectionInfo class to connect to O365. We use basic auth and are trying to upgrade to modern auth. I turned off basic auth in my tenant. Following this guide here, https://www.michev.info/Blog/Post/2997/connecting-to-exchange-online-powershell-via-client-secret-fl..., I am able to connect successfully in PowerShell by getting an access token and using New-PSSession cmdlet. I use the following commands:

Add-Type -Path 'C:\Program Files\WindowsPowerShell\Modules\AzureAD\2.0.2.140\Microsoft.IdentityModel.Clients.ActiveDirectory.dll'
 
$authContext45 = New-Object "Microsoft.IdentityModel.Clients.ActiveDirectory.AuthenticationContext" -ArgumentList " https://login.windows.net/mytenant.onmicrosoft.com"
$secret = Get-ChildItem cert://localmachine/my/thumbprint
$CAC = [Microsoft.IdentityModel.Clients.ActiveDirectory.ClientAssertionCertificate]::new(appId,$secret)
$authenticationResult = $authContext45.AcquireTokenAsync("https://outlook.office365.com",$CAC)

$token = $authenticationResult.Result.AccessToken
$Authorization = "Bearer {0}" -f $Token
$Password = ConvertTo-SecureString -AsPlainText $Authorization -Force
$Ctoken = New-Object System.Management.Automation.PSCredential -ArgumentList "OAuthUser@tenantGUID",$Password
 
$Session = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri https://outlook.office365.com/PowerShell-LiveId?BasicAuthToOAuthConversion=true -Credential $Ctoken -Authentication Basic -AllowRedirection -Verbose
Import-PSSession $Session

However, when I try to use C# WSManConnectionInfo to do the same thing, I get this strange error whenever I try to open the runspace:

System.Management.Automation.Remoting.PSRemotingTransportException HResult=0x80131501 Message=Connecting to remote server outlook.office365.com failed with the following error message : The WS-Management service cannot process the request. Cannot find the https://schemas.microsoft.com/powershell/Microsoft.Exchange session configuration in the WSMan: drive on the outlook.office365.com computer. For more information, see the about_Remote_Troubleshooting Help topic. Here is the code:

    public static Collection<PSObject> GetUsersUsingOAuthPublic()
    {
        var authContext = new AuthenticationContext("https://login.windows.net/mytenant.onmicrosoft.com");
        X509Store certStore = new X509Store(StoreName.My, StoreLocation.LocalMachine);

        certStore.Open(OpenFlags.ReadOnly);
        X509Certificate2Collection certCollection = certStore.Certificates.Find(X509FindType.FindByThumbprint, certThumbprint, false);
        certStore.Close();
        var cac = new ClientAssertionCertificate(appId, certCollection[0]);
        var authResult = authContext.AcquireTokenAsync("https://outlook.office365.com", cac);

        var token = authResult.Result.AccessToken;
        string auth = string.Format("Bearer {0}", token);
        System.Security.SecureString password = new System.Security.SecureString();

        foreach (char c in auth)
        {
            password.AppendChar(c);
        }

        PSCredential psCredential = new PSCredential(string.Format("OAuthUser@{0}", tenantId), password);

        WSManConnectionInfo connectionInfo = new WSManConnectionInfo(
            new Uri("https://outlook.office365.com/powershell-liveid?BasicAuthToOAuthConversion=true"),
            "https://schemas.microsoft.com/powershell/Microsoft.Exchange",
            psCredential
            );
        connectionInfo.AuthenticationMechanism = AuthenticationMechanism.Basic;
        connectionInfo.SkipCACheck = true;
        connectionInfo.SkipCNCheck = true;

        using (Runspace runspace = RunspaceFactory.CreateRunspace(connectionInfo))
        {
            return GetUserInformation(10, runspace);
        }
    }

I open the runspace like so:

    public static Collection<PSObject> GetUserInformation(int count, Runspace runspace)
    {
        using (PowerShell powershell = PowerShell.Create())
        {
            powershell.AddCommand("Get-Users");
            powershell.AddParameter("ResultSize", count);
            runspace.Open();
            powershell.Runspace = runspace;
            return powershell.Invoke();
        }
    }

The exception: Image of exception