I’m with AJB, the designer focused on the look, I made sure it work for me as the cook of the house.
Ours is mostly off the shelf bits but needed some customising to fit my hob, which is huge.
Also worth thinking about noise, not a single designer we spoke to considered it, we didn’t go top end so not that surprising, but things like having an in line motor for the extractor so it could be tucked over the utility out of the way have made a huge difference. Barely anyone I know uses their extractor as it’s so loud, whereas ours is virtually silent on low.