I agree, 1/4 inch even is big; 1/2 inch seems HUGE. Can you shift the range a little? Also, some of those T strips are wider than others. I had to return one set I ordered bcs it was too wide to fit. So do some looking around. They're easily found online, or at Bed Bath & Beyond, and they're inexpensive, and they work really well. (One nice thing; they can be removed to clean on and beside) This one is 2-1/2 inches wide; that ought to work. same brand, I think; different catalog I'm having trouble right now finding the SKINNY strips I needed to use.

It is 3/4 inch / 2cm. I dont know what they were planning to put there, he called it a scribe. I assume some trim to cover that up. That picture is only at the sink, here is the rest of it around the kitchen.I feel like some things were rushed, although I was in no rush, to get done for closing. There is other questionable quality on some of the trim, tile, drywall and texture (especially in the master bath and bedroom) as well throughout the house.

"What is considered the 'normal' width for the gap?" I'm assuming you're speaking of a freestanding range? If so, a gap between 30 1/16" - 30 1/4" would be considered normal. The countertop sides should be perpendicular to the rear wall and parallel to each other, no matter what the cabinets are doing.

You're mixing different terms, and that's causing confusion. A Bertazzoni is very much a consumer range and most definitely not a commercial range. You would never see it in a restaurant kitchen. The dimensions just wouldn't fit. And it probably also wouldn't stand up to the daily abuse. Also, most professional chefs would be put off by the small amounts of BTU. Professional cooking is all about speed. Most ranges start at about 30kBTU for all of the burners. What you have is a residential range that has been styled to look more like a commercial range and that has some of the features that would be useful to both a professional and a home chef. But it still has all the safety features and the dimensions of a residential range. That's why you can install it next to kitchen cabinets and why you can get away without a fire suppression system. And yes, there are plenty of those brands. People frequently refer to them as prosumer, as they want to establish a clear distinction from lower-powered conventional consumer models. But calling them commercial is highly misleading, as that expression is already in use for something very different.