Let me address the p-zombie first: it's a biological impossibly. Saying a p-zombie can be conceived of that has no inner feeling is like saying I can conceive of a philosophical star that radiates dark. Very nice that you can do that, but it's physically meaningless.
Why does biology preclude a philosophical zombie? Because every year we find new evidence of how utterly interdependent brain processes are and how tied to the experiential history of an organism.
We have mapped out the initial engrams that form in response to a new salient memory, and seen that 1. Time of day, 2. Physical location 3. Internal state all unique to the organism drive it's specific response, the specific way it saves the memory, etc.
That is, the organisms path history, it's interactions with the environment over space and time, shape it specifically based on the spaces and times IT experienced.
Take circadian rhythms, the internal timekeeping system all animals have. You feel it go haywire when you have jetlag. That is quite literally a history dependent response from your circadian clock to unexpected light.
Your p-zombie, if you specify it to have exactly your rhythms, will then need to have identical molecules being produced at identical times in every single cell, because that is how circadian rhythms are instantiated in all life, it's in each cell, and these cells can be synchronized, or, due to events like long distance travel or shift work, desynchronize. When desynchronized, you feel it, you feel different parts of your body adjusting, your meals shift, your taste and mood for food shifts...
Now, to put this in perfective, a human has about 36 trillion of their own cells, and an equal quantity of single cells symbiotes and commensal organisms, which give off all kinds of chemicals that shape, among other things, the circadian rhythms we talked about.
Now can you tell me: does the p zombie have not judt an identical compliment of 70 trillion odd cells, and they will all be in the same phase all the time as the cells in the non-zombie conscious person?
If so... How is this masterful phase synchrony across space achieved? What physical process allows for this?
If you cannot conceive of a way to do this synchrony (and you won't, basic physics forbids it), I think the sensible conclusion is to stop worrying about the philosophical zombies, and start looking at what information we have about actual humans and animals.
I brought up clocks to make a point, but actually, the evidence is building the biological clock is foundational for consciousness:
Some clinical signs: https://academic.oup.com/sleep/article/45/7/zsac094/6571981
And a broader theory:
https://pubmed.ncbi.nlm.nih.gov/34382225/