“Fry them in tallow.”
You would be hard-pressed to find any restaurant that fries its potatoes in tallow. The oil is important, to be sure. Some restaurants use duck fat which I’ve never tried, but if done right I expect are good.
A friend tells me air fryer fries are good, made with just a few spritzes of olive oil. A popular way of making fries used by tv chefs double fry them. First to partially cook the center, secondly fry them until they’re crisp. I would like to try doing that but haven’t yet.
I don’t think olive oil would ever taste as good for frying as tallow due to its lower palmitic acid content. Butter and cocoa butter are high in palmitic acid.