Since my hubby has gone keto and I have to stay low carb anyway we've found a number of restaurants that have lettuce wraps. Our favorite and what we think is best done is Jimmy Johns subs. For a fast food burger, Carl's Jr offers lettuce wraps.
They don't even blink when he orders a Double Quarterpounder with no bun at McDonalds! They have special clear trays they serve it in instead of a lettuce wrap.