Another series of games you might want to look at for building your own fleet are those set in the
X Universe.
And when I say build, I mean build. You buy/capture hulls and then must equip them yourself either by buying stuff from AI factories which takes forever, or more likely building your own factories and making all the equipment yourself.
This is lots more fun than it sounds.
X is a one player one ship affair. You can assemble a swarm of fighters from factories you own, but that's it.
X-Tension is the earliest game where you can command any class of ship and build an actual fleet. It is rare as rocking horse s*** so good luck trying to find a copy.
X2: The Threat is the first "all in" fleet simulator with a decent command system and (somewhat) competent AI. I have spend an inordinate amount of my time playing this game and filling the universe with factories. It is a little quirky due to the auto installer refusing to work on anything past XP. You can just drag everything off the CD patch it up and it works fine though.
X3 and it's many variants/spinoffs are not something I have any experience with, but they look like they are more polished versions of X2. Presumably with actual working installers.