Why root login fails after new RHEL 10 installation ?

Issue

• Freshly installed RHEL 10 disables root user login.

  rhel10 login: root
  Password: 
  Login incorrect
  
  OR
  
  $ sudo passwd -u root
  passwd: unlocking the password would result in a passwordless account.
  You should set a password with usermod -p to unlock the password of this account.
  

• Unable to SSH root user.

  # ssh root@rhel10
  root@rhel10's password: 
  Permission denied, please try again.