What's on the right side of the dishwasher? If there is a base cabinet filler face frame spacer panel anywhere on that base cabinet run, just either remove it, or reduce its width with a table saw. Then you can shift the dishwasher to the right, by an inch or two. Then, put an end filler panel right next to the oven, with a 1 or two inch face frame filler piece. This new end panel with face filler will allow you to build a 3/4" thick sub counter, to support your new counter. This is how it should have been done to begin with.

I've built a few dozen kitchens, including my own. I see a lot of Mickey mouse, hair assed ideas posted above here, LoL