Battlefleet Gothic 2 is in development.
https://store.steampowered.com/app/573100/Battlefleet_Gothic_Armada_2/
Scratch that I see its already out, and it looks like its 'still in development' regardless, given the review score
I was also eyeing this title, but I think I need a more convincing offer than what I'm seeing here.
Capital ships... you might find a surprisingly cool game within Space Engineers - basically Minecraft in space, with a pretty nice physics engine, inertia and all that other cool stuff. Its a very deep building game, and you can even add code to it/program blocks. Or just keep it simple and build a badass destroyer just the way you'd like it. Hangar bays, custom built fighters or remote controlled drones... all possible. The only limitation is what you want and can cook up. Its also in a feature complete and proper state right now (this wasn't always the case).
https://www.spaceengineersgame.com
Perhaps a somewhat similar idea to this (command of large things) with a turn-based approach is Battletech. But here the capital ship is just a base of operations. Still, it has very similar components to its gameplay to capital ship combat. The big ass robots are equally cumbersome and varied in their combat ability, it takes some proper planning to get things right, you get to target subsystems and use smart firepower to gain the advantage... It has a new expansion coming soon as well, lot of repetitive content but the combat system is very cool and you can customize everything. Good on a sale. Somewhat questionable at full price IMO.
Another peculiar suggestion I have for you is this one. A much lighter game, but lots of fun, balls to the wall broadside ship combat. Yes, broadside - its a 2D-plane game
https://store.steampowered.com/app/290300/Rebel_Galaxy/
And if you want more, much more of that and don't mind freeroam, poor campaign and simple mission structure/repeatable content (and full 3D-plane mobility instead):
https://store.steampowered.com/app/419480/Starpoint_Gemini_Warlords/
-- or Starpoint Gemini 1. Its a more condensed experience. Warlords takes everything to 11 really, and can be overwhelming. Personally had a bit of trouble keeping myself attached to this franchise after having played part 1. I burned out fast on Warlords, but YMMV.
I'll leave the other cool suggestions to Kursah because he's much deeper into space than I am (lol).