NetworkManager is the one exception I'm aware of here, but I don't think any server distros use it. Using NM is also the best option for configuring desktop environments, so I wouldn't bother disabling its resolv.conf management functionality.
Doesn't RHEL ship with NM by default? And test on its usage?
It can be worth trying to set the file to immutable;
chattr +i /etc/resolv.conf