Regarding soldiers, those are 2nd and 3rd hand reports – id like to see something from a gaol themselves, as the greater the claim one makes the more proof is needed to substantiate it. Being a milchemes mitzvah is untenable with people who don’t believe in the mitzvos to begin with. If an atheist makes a bracha, we don’t answer amen, because his bracha is not a bracha. Their kibush is not a mitzvah either, even if it fulfilled the necessary requirements (which it doesn’t, as there’s no king).
Malchua yisroel is even more contrived, as there’s nothing in the state that fulfills the requirements for malchus, including a navi for non davidic kings, shemen hamishcha etc