Builds done for challenges are designed usually for aesthetics and not gameplay. You want to focus on the visual if the lot is being toured on stream or featured in a youtube video. I recently did a shell challenge where we only had a 20k budget, so my build had more decor rather then skill building items.
My favorite builder is @DevonBumpkin . I can look at one of his builds and vividly imagine the type of sim who lives there, he really nails the environmental story telling. Beautiful exteriors and interiors, he lays out furniture like an interior designer. Devon also has quite a range, creating everything from little cozy cottages to sleek brutalist builds. I really really hope he is selected to design lots for the next expansion pack.