I think the concept of the game is good but could be made a lot better with a few gameplay changes.
Instead of seating the kinds yourself, they could walk up to tables automatically. This would force the player to always be on the move as they have to constantly react to what the kids want. Also, instead of having to wait for the food to spawn, every type of food could always be available to pick up, though your only able to hold one or two at a time. Alternatively, you could still have the player wait for food to spawn, but they have control over when the wait time starts. For example, they could put a pizza in the oven then have to wait a couple seconds until it's ready. They could also make multiple food types at the same time. While the pizza's in the oven, they could turn on an ice cream machine, then go back to pick up the pizza and hand it to a kid. These options would give the player more agency, giving the game more depth, as the player would always have to be planning ahead. It also means there's always something they can be doing, which I feel is very important in arcade-style games like this. Finally, instead of having to click to move Freddy, using the arrow keys to jump from table to table would be much more intuitive. You could then have a single button to pick up and place down food.
As the game goes on, kids would spawn more and more frequently. They could also lose patience faster or ask for multiple food types at a time. It could be endless, or split into levels, like my game was. And of course, if a kid runs out of patience, it's game over. Or the player could lose a life if you want to be more gracious. I think with these additions, this would make for a great Atari-style minigame, though you said you wanted to expand this into a full pizzaria simulator, so I'm not sure if this is the direction you'd want to take. Either way, I hope this helped.
-Jowski