To show two ships at once, yes. To show them seperately, which is what the original series often did? Different wuestion.
Huh? You did ask
"But if you want to show them being thousands of kilometers aparrt, how do you make that interesting to look at, is the question."
You can't show ships thousands of kilometers apart on any screen unless you reduce the ships to really tiny points of lights only distinguishable from the background starfield by the fact they move. I don't think many viewers would find that interesting to look at or not for very long.
Your only real options is to either do it like TOS in which the camera cuts back and forth between ships or do it like TNG in which they show ships close together and don't pay too much attention to stated distances.
What strategy?
Why not? I think submarine battles
occur when they know where their opponents are.
This is where the cloaking device was needed as a handwave to have a space submarine battle. Simple as.
Not simple at all, because you've totally lost me there. Cloaking devices can neutralize sensors, but that still doesn't mean starships shouldn't be equipped with them. If nothing else, starships need sensors in order to navigate between planets.