How to disable NetworkManager in RHEL?

Issue

• Disabling NetworkManager

  • What steps are needed to disable the NetworkManager service?
  • What is needed to ensure it does not start again on a subsequent reboot?

• Disabled NetworkManager but still seeing errors (need to fully disable)

  • Trouble configuring networking with NetworkManager and need to disable.
  • Disabled NetworkManager but still seeing errors about it and "Connection activation failed"