Yes, he doesn't really have anything to fear when he's up against ordinary humans with tanks and guns. Way to completely miss my point.
Literally every time Superman has fought against Zod, Mongol, Doomsday, Kalibak, Darkseid, Metallo, or hell, even just Luthor in his Kryptonite battlesuit, he's gone into the fight knowing that he could potentially die. Because in-universe, when you're not looking at things in terms of narrative and tropes and plot armor, the fact is that ALL of those villains could potentially kill Supes. In some alternate universes, they *did* kill him. We, the readers, know that DC isn't going to kill off Superman because he's their most popular character. But Superman doesn't know that. Yet he fights anyway, even knowing that every fight against one of those opponents could be his last, and that takes courage.