the Anti-spirals can alter time, space and reality (0:18 in the video below). I don't think it would be difficult to alter the appearance of things for the effect.
altering things is something that even franklin richards can do , nothing impressive. and when did they alter the universe?
that universe would be like going for a walk for franklin richards. it's so easy to alter. if the universe was altered then you can't compare sizes. galactus in that distorted universe would look bigger than those robots.
besides they can alter time, space, and reality, but they can't alter the robot?, they have that power and they have to fight hand to hand and with lasers?.