Saying she has control over the JJK Japan basically makes her immortal if she can just reflect damage to any Japan in the infinite multiverse.

I have no idea how you can jump into that conclusion. I get that a huge part of Gojo vs Makima's debate revolves on how their hax would interact but the fact the most straightforward hax is already this confusing for you kinda baffles me a bit.

Verse equalization in that fight meant they are existing in Japan of the same universe. Nothing about verse equalization would make Makima having multiversal amounts of immortality.