[Eclectic Kitchen[(https://www.houzz.com/photos/eclectic-kitchen-ideas-phbr1-bp~t_709~s_2104)

I don't think you need a break in the shelves above the sink unless they are really deep. You could even mock it up if you're not sure.

I have very low cabinets (10" above the counter) which are also 18" deep above my kitchen sink so they are a little imposing if you stop yo think about it, but I actually don't notice it when I'm washing. I also don't have a dishwasher so I am always doing dishes. I've only bumped my head once on the cabinet, and that was when I was trying to look straight down the drain.

This is only a bar sink, so maybe not relevant for you, but here's my long butcherblock shelf (6') that's 18" above the sink. The shelf is 12" deep, so plenty of space to hold dishes. (Although we use for glasses and dessert plates)