Using the earth's own gravity as an energy source can be activated, but it can only be moved once and will not be used to move further, because this is potential energy work. After the work is done, the potential energy will be consumed.
In fact, hydropower uses potential energy to do work, but water is constantly rushing down. There is endless potential energy in the upstream flowing down at a certain speed, so it can continue to emit some water.
This cannot be considered permanent motion, and potential energy cannot be recovered and reused.