Update Office 365 Owners MS Graph Client

using OfficeDevPnP.Core.Framework.Graph;
using Microsoft.Graph;
using Microsoft.SharePoint.Client;
using Microsoft.IdentityModel.Clients.ActiveDirectory;

var authenticationContext = new AuthenticationContext(authString, false);
// Config for OAuth client credentials 
ClientCredential clientCred = new ClientCredential(clientId, clientSecret);
AuthenticationResult authenticationResult = null;
string token = "";
Task authtask = Task.Run(async () => authenticationResult = await authenticationContext.AcquireTokenAsync(resourceId, clientCred));
authtask.Wait();

//List of Owner Emails
List<string> Owners = new List<string>();

if (authenticationResult != null)
{
    token = authenticationResult.AccessToken;
    
    var group = UnifiedGroupsUtility.ListUnifiedGroups(token, mailNickname: alias).Where(result => result.MailNickname.ToLower().Equals(alias.ToLower())).First();
                    
    if (group != null)
    {
        string groupId = group.GroupId;
        if (Owners.Count > 0)
            try
            {
                Task runTask = Task.Run(async() => await updateGroupOwner(token, groupId, assetOwners));
                runTask.Wait();
            }
            catch(Exception ex)
            {
                log.Info("Exception while adding owners " + ex.Message);
            }
     }
}

private async Task updateGroupOwner(string token, string groupId, List<string> assetOwners)
{
    GraphServiceClient graphClient = new GraphServiceClient(new DelegateAuthenticationProvider(
                                            async (requestMessage) =>
                                            {
                                                if (!String.IsNullOrEmpty(token))
                                                {
                                                    // Configure the HTTP bearer Authorization Header
                                                    requestMessage.Headers.Authorization = new AuthenticationHeaderValue("bearer", token);
                                                }
                                            }), new PnPHttpProvider(10, 500));

    var groupToUpdate = await graphClient.Groups[groupId].Request().GetAsync();

    foreach (var o in Owners)
    {
        var ownerQuery = await graphClient.Users
          .Request()
          .Filter($"userPrincipalName eq '{o}'")
          .GetAsync();

        var owner = ownerQuery.FirstOrDefault();
        if (owner != null)
        {
            try
            {
                // And if any, add it to the collection of group's owners and members
                await graphClient.Groups[groupToUpdate.Id].Members.References.Request().AddAsync(owner);
                await graphClient.Groups[groupToUpdate.Id].Owners.References.Request().AddAsync(owner);
            }
            catch (ServiceException ex)
            {
                if (ex.Error.Code == "Request_BadRequest" &&
                    ex.Error.Message.Contains("added object references already exist"))
                {
                    // Skip any already existing owner
                }
                else
                {
                    throw ex;
                }
            }
        }
    }
}