create my own vending machine

I have an idea of how i would work this project but i accept suggestions:
I want to build a home project selfservice car wash. For that i can easily setup a shelly that turns on and off whenever i want the energy for an eletric pump attached to 2 water containers (one with just water and other with water with detergent). The help i need is to integrate this automatically with a payment process, bills and coins (Euro). So I will need a display (so the user can see how to purchase the minutes to have the electric pump available and the minutes left), a coin and bill acceptor. Whenever a certain amount is given, automatically gives energy to the shelly device and let the water runs. i would like to use a raspberry pi to make all this work and programmed by python code. As much simple as possible. The idea is also monitor remotely the money received and if some problem arises with the payment (the user calls me for example) i can remotely skip the payment process and make it work no matter what (that is why i thought about shelly because i already worked with that and for me is smooth enough).

I need someone to help me with the items to buy, circuit to build and how to do it, and program it for me.