A set is $\mathsf{P}$-immune iff it has no non-trivial $\mathsf{P}$ subset.
Is every $\mathsf{coNP}$-complete language $\mathsf{P}$-isomorphic to an $\mathsf{P}$-immune $\mathsf{coNP}$-complete language?
Joshua Grochow's answer to my previous questions shows the answer is negative assuming cryptographic conjectures. Is it possible to show the answer is negative only assuming $\mathsf{P}\neq\mathsf{NP}$?
Or show the answer as positive with additional assumptions.
As @Kaveh points out based upon a P isomorphism assumption (Bertman-Hartmanis conjecture) one only has to show the existence of one such language.