Begin by making the cheese sauce: In a small bowl toss together the cheese and cornstarch. In a three quart saucepan, bring the milk to a simmer. Turn the heat to low and whisk in the cheese. Whisk until the sauce thickens. Pour it into a bowl. You can reheat it in the microwave for a minute right before serving.
Next, make the tater tots: Bring a three quart saucepan, half full of water, to a boil. Add a tablespoon of kosher salt and the potatoes. Boil them for ten minutes. Drain them and let them cool, until they're no longer hot.
Shred the potatoes on the small holes and put them into a bowl. Add the onion, garlic, thyme, salt, pepper, and flour.
In a Dutch oven, bring an inch of oil to 350 degrees. While the oil heats, roll the potato mixture into one inch balls. It helps to oil your fingers when doing this.
Fry the potatoes in four batches, dropping them in one at a time. Fry each batch until they're golden brown, for about three minutes. Don't add another batch until the oil goes back to 350 degrees. Drain the tots on a wire rack over a pan. These can be made ahead and reheated in the air fryer.
Place your tots on a serving platter, and top them with the cheese sauce and the vegetables.