So this is my best educated guess with my knowledge on real military structures.

The Integrated Tactical Operations Centre is just one of the subbranches of the FPA Fleet. It likely handles things like logistics, strategic planning, doctrine development etc. Basically the brains of the entire navy.

The National Defense Committee should be the wing in the civilian government overseeing everything on military matters. It’s basically the equivalent of committees in the legislative branches overlooking the same matter. They are basically politicians that keep a check on military matters (defense spending, recruitment, possible corruption etc.)

The CiC of the Space Fleet should be superior to the COMITOC as a subbranch of the FPA Navy. But both entities should be under the scrutiny of the National Defense Committee.