relationship between "Total users", "Users", "New users" and "Returning users" in GA4

I'm curious about the interrelation among "Total users," "Users," "New users," and "Returning users."

1. How does "Total users" differ from "Users"?

2-1. Is the equation (# of total users) = (# of new users) + (# of returning users) accurate?
2-2. If 2-1 is accurate, where can I find the # of total users in the GA4 report?

Thank you.