This is a simple solitaire card game to show how to use Nez frame work. This ECS Framework specifically made for C# and Monogame.
https://github.com/prime31/Nez
I worked with Monogame, then went to Unity, and now came back to Monogame using Nez because I like the simplicity of working with Nez on 2D games. This is a powerful 2D game engine.
ECS is used to allow for separation of concern when coding. For example, I choose to update my components using a separate "System".
However, You will find most examples of NEZ to be using updates inside "Components". I don't like that. NEZ is flexible enough to allow you to choose which way to go !!
Game uses UI Canvas to put 2 button and a label on screen.
ECS explained here https://www.gamedev.net/articles/programming/general-and-gameplay-programming/understanding-component-entity-systems-r3013/