Since I no longer have the spark of youth I once had, I've decided to go ahead and archive this repo. If I ever do manage to muster up the motivation to work on a game project, I'll be making use of an engine, so I don't have to worry about writing one from scratch. Monogame is a fantastic framework if that's what you want to do, however, but it's not for me anymore. For any further developments on Monogame, I encourage you to check out their website, or the archive repo linked below.
A direct port of the Game State Management sample for XNA 4 that used to be found here, to Monogame. It seems to have since been moved or deleted, but the license and everything else can now be found at this link.
There is a very good XNA Game Studio Archive repo that has a lot of XNA Game Studio education content, including the original version of this repo, if you need more than this.
This is currently working while targeting netcoreapp3.1 and the version of Monogame that comes with the template found here - MonoGame (.NET Core)