Profiting off of city income is extremely difficult right now. You will probably fare better playing the market, holding, or participate in the liquidity pool.
If you actually want to build a city right now, it needs tax reduction buildings such as law firms and churches. Then, there are % income increase cards such as mining to help along.
Even with those upgrades, I am only able to take in like 300 SIMs out of over 17K produced by my city a day.
When the war tax is on, it helps to have those war buildings. As you can see in the screenshot, 91 shares (0.711%) of all war shares grant me about 6K SIMs a day despite of the insane taxes.