Upgraded food markets should have customizable ports.

Providing it with two food types that use flat conveyor belts is very clunky with only one flat conveyor intake.

yeah i definetly feel like food markets II should have 4 inputs 2 for flat conveyors and 2 for u-shaped conveyors, water supply stations for settlements even have 4 connection points, so food markets should also have them

Food Market 2 is actually just bad.
Out of 10 possible foods, only 2 of them use loose storage: Potato and Corn. This means that, for double the manpower, and more than double the resources, and no capability to attach both ports direct to storage, you can only fully utilize both halves by just flooding your city with potato and corn. You still need at minimum 8 food markets to supply all food items, which doesn't even save manpower - it only saves 2 building slots, which it the least necessary thing to save. They don't even store more of each item vs Market 1.