How to create CrmServiceClient instance in .Net Core 3.1?

I tried this code:

using Microsoft.Xrm.Sdk;
using Microsoft.Xrm.Tooling.Connector;

var connectionString = @"AuthType = Office365; 
                         Url = https://myorg.api.crm8.dynamics.com/XRMServices/2011/Organization.svc;Username=user@azureresulticks.onmicrosoft.com;Password=***";

CrmServiceClient conn = new CrmServiceClient(connectionString);

IOrganizationService service;

but I'm getting this error:

on trying to create the CrmServiceClient instance.

The same piece of code was working in .NET framework versions.

But this time, I have to use .NET Core.