The physics of the universe are rather well known. And so are the distances.
Light only moves so fast. If you (somehow) move faster, then no one can see you coming. Like the bullet that travels faster than sound, it arrives before it is announced.
Distances in space are vast beyond comprehension. Looking for a fleet in interstellar space would be near impossible, not only for the problem of detecting emissions the only move at the speed of light, but the vastness means that meeting for combat would be so improbable that the chances of it happening wouldn't occur before the end of the universe.
Using the 1700s as an analogy, fleets at sea found it hard to locate each other in the proportionally smaller oceans. Even with radar and satellites it's still tough.
It would be like trying to find a specific grain of sand located between the earth and the sun.
It is possible to detect reasonably sized and reflective/emmissive objects in the solar system but all those sightings are historical by hours to weeks depending on how far out the object is.
Even if you had some sort of FTL sensor, distances degrade resolution to a degree that again it becomes useless for general searching quickly.
Battles in deep space simply aren't going to happen. And strategically you wouldn't want to do it anyway as you'd want to keep your war assets close to whatever is valuable.
There's no possible mechanism for 'space stations' located in a particular solar system to influence anything out side that solar system. In fact it would be difficult to have influence beyond the planet it's orbiting. It's inane for a space story or game.
These two game mechanics are simply ridiculous.
The wildest theories on how FTL would be accomplished all point to it being extraordinarily expensive in energy use and requiring exotic materials that don't exist outside of theory.
So if in the game or story using FTL is common as getting in your car, the game or story going to feel silly and improbably. Like the early speculations that we would all travel by personal jetpack or have our own personal balloons to carry us about.
Unless of course this is a game based upon 'The Jetsons' and you can flit to another planet in the family car in a few minutes. Or you're Fred Flintstone and it's practical and desirable to push a cart of made of logs and stone wheels to and from 'work'.