In my view withe the top of the fridge that close the sink is not in a good position and not fit for purpose there should be room for at least a flat type trap and the pipes.
My solution would be raise the worktop by an inch or two but without seeing it that may not be possible.
Good luck with it hope you get your money back.? these manufactures need to get interior designers that have practical experience before drawing up plans.????
What’s the point of fitting a sink unit that does not drain correctly absolutely ludicrous?
From the MMM review on youtube, raising the worktop by up to 5cm looks doable without spoiling the kitchen. A competent chippie could make it look acceptable.