Welcome to our little community!
In order to run the Netdata Agent without Cloud connectivity, you can start the container and edit the configuration to disable Netdata Cloud.
You can read more about the container and how to edit the configuration in the documentation:
In order to disable Netdata Cloud, you will need to make these changes to the configuration:
Since the container is already built, you can only disable Netdata Cloud at runtime, since the Agent is already built with the ability to use Netdata Cloud.
Out of curiosity (and some product feedback), what’s your use-case and why do you want to disable Netdata Cloud altogether?