Help Building A Simple Raspberry Pi Game Controller

Need to build a simple game controller with the raspberry pi zero AND pi pico(or just a pi zero), that can play computer games and has computer mouse functionality... I prefer python as the codebase... I'm open to arduino as well but I need the pi zero to be able to run a specific raspbian software on its own and have its own controls... I believe assembling this game controller is a similar process to building a handheld gaming console BUT I don't want the pi zero to run a gaming software, I'm going to put a unique raspbian software on it... Also, would need both(if you use the Pi Pico and Pi Zero) to be able to connect to a computer via a the SAME USB and/or USB-C to play games, operate as a mouse, and I need the pi zero and it controls to have specific functionality outside the game controller aspect. Drawing attached is the concept of a game controller aspect(that plays games and has mouse functionality) and the pi zero running a its own unique raspbian software... The pictures attached are various pictures of TWO required components. Didn't take a picture of the pi pico because I'm not sure if you need it to build this game controller. Link to Pi Zero OLED Header Video: [login to view URL] Not concerned about the design, as long as it works.