I think the closest to what you ask is the Swiss democracy (Swiss political system). Here's a video that explains how it works and the difference to all the current political systems:

https://www.youtube.com/watch?v=2d9xHeY1vBM

Also the website:

https://thedemocracyupgrade.org/

Switzerland is one of the freest country in the world. My argument is that it is so because it's actually the only democracy in the world.

Each canton has a constitution with independent police, courts, health, education, taxation system.