Ducks shouldnt be kept as solitary animals. So you need a second duck, which means you need more room to keep them in.
There's no reason to take a duck into public. They're not dogs, they're prey animals at their core and are very easily spooked by literally everything.
Ducks poop literally hundreds of times in a day, you said you only plan to diaper it when it's "in public" but you also plan to keep it indoors....it will destroy your house. Unless you're keeping it penned inside your house in which case....why? A big enough 24/7 pen for two ducks is taking up basically an entire room of your house. You're working 8 hours a day, they deserve to be in an adequately sized and safe pen outside.
Overall it doesnt sound like ducks are your best choice. A dog, a cat, even a different bird would be a more suitable option