How to disable SSH root access and create other user

Hi everyone,

I would like to enable port forwarding on my router to reach my laptop with Red Hat from outside in SSH but I would not want to do it as root but with another limited user and then once logged in change with the command su -.
Can you tell me the steps that I have to carry out and how should I intervene at the configuration level?
And can you also tell me how to make access safer, perhaps through the use of certificates and how to generate them?

Thank you all.