Awesome and creative setting. Enjoyable to read. Very surreal... Fun to think about, but that works at your disadvantage when it comes to making an actionable system. Establishing a clear place, challenge, or goal to start from is difficult. It sounds like mostly metaphysical combat, but I have a body stat. Lean into the weirdness with a more intangible thought-exercise kind of system, or give something very specific for players to gear towards.