Is that an outside wall? If so why not not just get a different hood to vent at the top instead

That hole isn't high enough to work with a rear venting hood. The hood would be higher than it is. You need to access the duct from a different point. That wall needs to be opened up and the duct altered, so at that point, you're doing enough drywall work etc. that you might as well do it through the ceiling or wall, or wherever the hood that you like demands.