In this context, would it be possible for "άριστη" to mean "beautiful", or is "beautiful" just "όμορφη"? Thanks for the help!
Many words may convey a similar meaning, but all Duolingo courses try to keep things simple, especially for learning purposes. I'd say that exquisite better translates to θεσπέσιο. I personally mostly use it (not that often) when referring to delicious food. Adjectives can be a hard topic to cover, translation-wise, so it's always better to stick to 1-2 translations that are easier to memorize ;)