"Chess, but..." series

Would be great if you could script/ run mods onto the default chess game from which figures even exist to how figures work. Excuse if it already exists and I'm just dumb, but it would be cool to be able to add mods onto chess.com, and then having the engine analyze possible games with those modifications.

Example modifications could be:

• All long-range figures can jump over their own colored units but not on them. So could the white bishops quickly get into the game area, how would gameplay be affected? The engine could come in handy to analyze those.
• Redefined figure movement: I mean just generally mess up with chess. Have the king only move on the diagonal four squares around him, allow the queen to jump like a horse in addition, allow pawns to generally move to the four aligned squares and eat diagonally to the four squares, with the ability to retreat and horizontal movement.
• Different chess board and new figures.
• Different goals and eating mechanics, a different game with only chess as base.

After 4,000 years, chess players will finally be able to update the game.

That thing with the engine is just, that stockfish can't handle custom pieces, as far as I know.

I think Fairy-Max, by @HGMuller uses an external configurationfile containing the piece movements. That allows for certain changes to be done without having to alter the code and compile it.

https://home.hccnet.nl/h.g.muller/CVfairy.html