Use the Microsoft.Identity.Client to acquire a token from AD for your daemon or service (using client credentials).

AcquireTokenForClientFromAD.cs

namespace GetToken.Console
{
    using Microsoft.Extensions.Configuration;
    using Microsoft.Identity.Client;
    using Microsoft.Identity.Web;
    using System;
    using System.Globalization;


    public class Program
    {
        
        public static async Task Main()
        {
            /*  
             *  /appsettings.json
             *  {
             *      "Instance": "https://login.microsoftonline.com/{0}",
             *      "ApiUrl": "[Enter app url eg. https://graph.microsoft.com/ or https://management.azure.com/ or https://my-app.eastus.kusto.windows.net/]",
             *      "Tenant": "[Enter here the tenantID or domain name for your Azure AD tenant]",
             *      "ClientId": "[Enter here the ClientId for your application]",
             *      "ClientSecret": "[Enter here a client secret for your application]"
             *  }
             */
            AuthenticationConfig config = AuthenticationConfig.ReadFromJsonFile("appsettings.json");
            

            IConfidentialClientApplication app;
            app = ConfidentialClientApplicationBuilder.Create(config.ClientId)
                    .WithClientSecret(config.ClientSecret)
                    .WithAuthority(new Uri(config.Authority))
                    .Build();
            app.AddInMemoryTokenCache();

            string[] scopes = new string[] { $"{config.ApiUrl}.default" };

            AuthenticationResult result = null;
            try
            {
                result = await app.AcquireTokenForClient(scopes)
                    .ExecuteAsync();
                Console.ForegroundColor = ConsoleColor.Green;
                Console.WriteLine("Token acquired");
                Console.ResetColor();
            }
            catch (MsalServiceException ex) when (ex.Message.Contains("AADSTS70011"))
            {
                // Invalid scope. The scope has to be of the form "https://resourceurl/.default"
                // Mitigation: change the scope to be as expected
                Console.ForegroundColor = ConsoleColor.Red;
                Console.WriteLine("Scope provided is not supported");
                Console.ResetColor();
            }

            if (result != null)
            {
                Console.WriteLine($"Access Token: \n{result.AccessToken}");
            }
        }
    }

    public class AuthenticationConfig
    {   
        public string Instance { get; set; } = "https://login.microsoftonline.com/{0}";

        public string ApiUrl { get; set; } = "https://graph.microsoft.com/";

        public string Tenant { get; set; }

        public string ClientId { get; set; }
                
        public string Authority
        {
            get
            {
                return String.Format(CultureInfo.InvariantCulture, Instance, Tenant);
            }
        }
        public string ClientSecret { get; set; }

        public string CertificateName { get; set; }

        public static AuthenticationConfig ReadFromJsonFile(string path)
        {
            IConfigurationRoot Configuration;

            var builder = new ConfigurationBuilder()
             .SetBasePath(Directory.GetCurrentDirectory())
            .AddJsonFile(path);

            Configuration = builder.Build();
            return Configuration.Get<AuthenticationConfig>();
        }
    }
}