I'd be equally or more concerned with the differences, if any, in height of the induction cooktop and the body (not the grills) of the gas cooktop. I would think you'd want surface of the induction unit to be level with the surrounding cooktop, neither above nor below it.

An owner on AJ Madison complained that the induction elements are only 4" in diameter.

Look up the manufacturer's installation instructions for rear splash clearances please.

You have to deal with the side of the cooktop as it relates to the cabinets also. I would consider using black granite to fill the front and top area with a bull nose on the front lip. A piece at the back as necessary. Then choosing a Bosch or Miele cooktop.

Yeah, the cabinet front is a problem with rangetops if you later decide you want something else. I would do it right and choose a good 36" induction cooktop, replace the counter to fit and get a good cabinet maker to match a piece of cabinetry to fill in the front.

And amidst all this complexity, it may prove useful, either as splash clearance or cooktop support, to bump out the two support cabinets so cooktop support can be added where required. This will require some cabinet side finishing. If a drop-in surface cooktop is used, with embedded controls, pseudo drawer faces will be needed. My cooktop portion of my cooking peninsula is bumped out about 4 inches.

Here is a table, probably out of date but useful as a template, comparing certain candidate 36-inch induction cooktops I was considering in 2015 as replacement for a failed Kenmore (Electrolux) cooktop. (I selected the Frigidaire Gallery for the replacement, and so long as I keep paying for an extended warranty, it keeps on running.)

i would just replace the granite behind with all black, run it up to the ceiling, will look intentional. (also replace the outlets with the white, they hurt my eyes)

If you do not want to turn this into a full on kitchen remodel and spend 10's of thousands of dollars this is still a pretty easy replacement. The Bertazzonie range top looks like the sides are finished. Take out the existing cooktop and put in the new one. The width should not be a problem. The height will be different, I would just build a support for the new range top to sit on and have a local metal shop make a piece of stainless steel to finish the front of the support. It will be under the new top and with stainless steel it will look like it was part of the range top, it looks like it will need to be 2-3" tall, no big deal. The new top will stick out a little but I think it will be better than trying to add a different piece of granite to the front if you go with a drop in cooktop. that will look like it was done to cover up a mistake. If you are happy with the existing countertop and cabinet finishes this is a much less expensive way to go. If you like the new range top and do want to remodel the kitchen in the future you can reuse the range top and integrate it into the new kitchen. Replacing the splash looks like it would be many thousands of dollars. With some planning this can be done in a day or two at the most and you can be back up and running with minimal down time.

You'll need to add a 50 amp, 240 volt circuit at the rear of the cabinet below the cooktop and in the location specified by the installation manual.