I see your airlines now.
First of all, you're not a noob with such a big airline to ask at the "new players" section (take it as a compliment).
Second, are you actually sure you're asking about domestic routes?
If you really must reach 200 gate limit and you really need more than 3000 destinations from one mid-sized airport, and you're at the same time so massively over-spamming capacity for routes you are holding by yourself by some 5-10 times from nominal demand and killing your profit, I just don't know what are you asking for here...
For me that doesn't make much sense (I go either for some "realistic" quality small or mid-sized airlines, or a massive 5000+ fleet trillions of profit and #1 ranking domination from some bigger country), but this is an open-end game, so if that's your thing...
You have a request that you must find an answer for by yourself because very few have tried something with the same mission...
Most people here ask what's profitable to get an airline off the ground, then some discuss what's even more profitable, or raising reputation or saving money, or what would be realistic.
This is just, well, special.
By the way, A350-900R, completely opposite of domestic, but has high capacity and relatively short runway demand. But I don't get the point.