There are two ways to work as the root user, the old way and the new way.
SU is the old way, and you will mainly use it in RHEL 10 to switch your current user
account from a shell environment, which is useful for testing all the users that you
may have created.
If SU is used with the minus option, the complete environment of the target user is loaded.
You should always use SU with the minus option to make sure that all your environment variables
are set the right way.
And while using SU, you need to enter the password of the target user.
If the root user has the password, SU minus can be used to open a shell as the root user.
But that is considered bad practice, so don't do it.
Better use sudo minus i instead.
If you use sudo minus i, you are prompted for your own password and not the root user
password, and that makes it already better.
Apart from the fact that in a sudo minus i environment, you are not a root everywhere
in your environment.
So the SU command is not what you use to escalate and run tasks as root, just use it for testing
all the user accounts while working with permissions as discussed later.