Nah, the self is the series of electrical signals in your brain. The self is composed of memory, emotions, thoughts, and personality, those are the things that make you you. Memory, emotions, and thoughts are in the brain and personality is basically derived from those (i.e. life experiences).

A brain in a jar may have no inputs or outputs, but it could still be cognizant. It might not be an amazing experience, but it would be. Your thoughts would still be going. It also could have inputs and outputs through a brain computer interface.

Think about your inputs and outputs. You’re still the same person if you go blind, deaf, mute, lose your limbs, whatever (although from that point forward you'll have radically different life experiences). All of those senses are ways for the brain to navigate the physical world it exists in. They influence the self, but they are not the self.

look at the brain-body system more holistically all of them act in unison to support each other

Yes, but that doesn’t make it all part of the self. It’s a complex system but it’s all to keep the brain alive.

Think about what death, cessation of the self, is from a physical standpoint. What forms of death are there? What physically happens in those forms of death? The answer is that brain death is the only actual form of death, everything else is brain death resulting from [whatever]. Some system in the body fails, ultimately stopping oxygen from reaching the brain, which means it stops working.