Yeah, But in lore they pretty much used exactly what those enemies are like, And vex= reality altering time traveling immortal robots that used to be biological- so do necrons Hive are planet eating creatures that consume for a god- so do Tyranids (even design is similar here) Cabal- emperor worshiping humanoids with a main base on Mars, have legions, have certain members devoted to psychic powers, nuke planets for being in the way- so do space marines again similar design.