What is the best network approach for a fps coop game?

Hello, i’m working on a coop fps game that has rpg elements (inventory, character customization), openworld, 4-8 players and i would like to know if you recommend doing most things on the server like storing each player inventory, handling gunplay (for example hit detection), etc or just do it locally on the client and only transmit to the server the bare minimum that the other clients need to know. Since this is a coop game i’m not very worried about cheating, my main priority is the net code to be fast and easy to manage.