When I create a new ASP .NET Core Web-Application, I can right-click the project in Visual Studio, and I see a context-menu entry called \"Manage User Secre
with and save. Now you can access to manage user secrets menu, edit it and save. Then you have to restore the first line of the csproj file to its defaults to be again a console app.
It's stupid but it works. Remember replace the usersecretsid property for every project or will just have one secrets.json for all your projects.