TenForward: Where Every Vulcan Knows Your Name

Virtually all sci-fi involving ships fighting in space uses a World War 2 aesthetic. Star Wars, especially. "Fighter" ships that fire "laser cannons" that travel in the direction of the flight of the ship is right out of how WWII fighters worked. Bigger ships with guys in turrets trying to shoot at those fighters, that's right out of how WWII bombers like the B-17 defended themselves. Space stations or huge capital ships firing really big guns, that's just like flak cannons in WWII.

Star Trek is a bit different especially because phasers are very fast (but not light speed). But they do ship-to-ship combat a bit like battleships shooting directly at other battleships. Sure, they have photon torpedoes, but they seem to be rarely used and they fire one at a time. And again, "torpedoes" are a very WWII weapon.

Virtually every other sci-fi show or movie does something similar: Stargate, Babylon 5 (at least they do space-inertia properly though), Farscape, Battlestar Galactica, etc. The only one that seemed a bit realistic was The Expanse, where a lot of things happened well beyond visual range, and guns were mostly about point-defense from incoming missiles.

As for what realistic distant future space combat would be like, it's really an interesting concept. In some ways it's like submarine combat in that there's no horizon, things don't need to spend energy to remain "floating" in place, and there's essentially no chance of outmaneuvering weapons. OTOH, one of the defining features of submarine combat is stealth, and in space it's much, much harder to hide. So, it would probably be about attempting to hide while using decoys. And, probably using remotely controlled weapons platforms that used lasers to try to smoke something detected at many light-minutes distance.

Like, instead of an armored battleship duking it out with another armored battleship, you'd probably have a command capsule that was as small and as stealthy as possible. It would communicate with scanning and weapons platforms using some kind of tech that wasn't detectable at range, like using lasers instead of radio, or maybe even using a very long cable. But, definitely no radios because they broadcast too widely. Any active scanning would make the scanner a target, so there wouldn't be anything valuable on the scanning source. You might even make it so that the radar / lidar emitter was separate from the receivers so that when the emitter was smoked, you didn't lose the detectors too. Any weapons platforms would also be immediately targeted as soon as they started firing, so you'd either use a launcher that was disposable as soon as it finished launching, or a nearly disposable laser turret type thing that you'd expect to be destroyed almost as soon as it started shooting. But, I think the biggest focus would be on decoys. In the ocean you can just hide in all the background noise from the ocean. In space, you'd have to make your own background noise.