Feel free to replace some of the ketchup with sour cream for less tomato flavor.
The ketchup recipe in the THM cookbook is a great no-sugar-added ketchup. (It can be hard to find no-sugar-added in stores).
For a gluten-free option, serve over veggies and use an allergy-friendly Worcestershire sauce replacement. || For an egg-free option, replace the mayonnaise with sour cream. || For a dairy-free option, use a homemade mayo made with olive oil and egg, omit the cheese, and make up for it by adding extra mayo and almond milk and some nutritional yeast. || For a nut-free option, use carton coconut milk in place of the almond milk. (Most people with nut allergies can handle coconut products, but check with your doctor first to make sure.)