If you make some off-the-shelf frozen-food-aisle french fries and fry ‘em up, drain and let ‘em cool on paper towels, salt ‘em and then bake ‘em hot again…they’re a reasonable facsimile of McDonald’s fries.
Do they come pre—fried? There has to be a reason why, when you make fries from fresh potatoes at home, yours get soft when cold; but McDonalds get hard as wood when cold. You could hurt someone with one of the sharp ones.