"Implement MQTT authentication for client side"

i need to hide credentials on the browser page and also create many MQTT clients users for every user, so that i will set the credentials on the CPU of the IOT device. The second IDEA is to create a new client credential for every user, so if a hacker gets this credential will not be able to manage others clients or users. The issue is that if use F12 on any web-browser will show credentials on the page.