Manipulating space and time may not be as scifi as we tend to think. Your brain manipulates time. Or at least how you perceive it. Like when you're extremely bored to the point where it's agonizing to the point that it cripplesv you, and you can feel the weight of every slow tick of the clock. Contrasted when you're having the time of your life and you blink and 3 hours already went by. Time didn't necessarily change, your brain changed how you perceive it.

Maybe the weapons we have manipulate your space time, rather than thee space time.

Or maybe we do just have insane crazy weapons/ items that literally manipulate space time. Just a thought