The Foundation book series, IIRC, has "disintegrators", which are invisible beams that disrupt the charges of the target atoms and cause the target to lose all chemical cohesion. However, "invisible beams" work poorly for video. As a result, most sci-fi video weapons have the huge disadvantage of forming an arrow pointing directly at where you are. Real firearms have muzzle flash but that has nothing on a huge finger pointing right at you.

Additionally, since the audience needs to "see" the beam, most sci-fi weapons have miserably slow firing rates, enough that on the modern battlefield they would be useless.

"Guns in general seem like something that should already be antiquated."

This comes from a mindset that technology is "tiered" and that later technologies are "better" than earlier ones in all ways. This is caused by watching too much science fiction and/or playing too many video games. It is not how the real universe works. In reality, throwing things really hard at your opponent is likely to be a viable strategy indefinitely. The science fiction technologies that would invalidate this, like Dune's shields, do not seem to be things that exist in the real universe.