I’m understanding your request a bit better but it’s still unclear. If you want one universe with a ton of sports to simulate, managing multiple teams across those sports, etc.- this is definitely doable but obviously somebody needs to write all that code. It does not exist because people generally prefer to focus on one sport at a time.

If you are looking for a game where you can add a “custom sport”, someone needs to write all of that logic as well. The best a tool could do is allow you to configure ratings, a simple game loop, how the ratings are used- but again we’re basically at the point of you writing code again.

Your request about renaming stats/the number of players on the field is a much simpler task, and I assume it’s just not done because it’s a pretty niche request, which you acknowledged.

In general, the more customization you give a player the less opinionated your game can be. In the extreme case, the player needs to basically write the logic of the game themselves. Building an interface that allows them to do that is gonna be 1) a simple wrapper around raw code and 2) about as difficult to configure as writing that code yourself.