Your question lacks specificity so you are going to get a circle jerk of answers that will lead you down a dark alley and shoot your parents turning you into Batman.

Plainly state your form factor. Combo means different things to different people.

Stackable is form factor that many apartments or small areas use where the washer is on the bottom and the dryer is on the top. These are usually matched units by one maker.

Combination AKA all in one is a form factor that many apartments or small areas use where there is one unit that you program to wash....then dry....all within one form factor.

Which of these are you talking about? If you are talking about one unit AKA combination then there have never been any BIFL ones spoken of here before. And, while these are a thing, these are tiny, tiny, tiny units and you will be doing laundry 2-3 times a week vice once a week.