So the main issue with double sided whetstones is that as you use any whetstones they “dish”, so if you use both sides it ends up being way harder to keep them flat. The “combo” stones tend to be lower quality in general as well

You’re usually better off getting a normal stone, then sharpening using only one side of it. A decent 1000 grit alone is good for sharpening undamaged kitchen knives. Don’t need a strop or a super high grit stone or anything you can just do stropping passes right on the same stone. But overall it’s not really that serious, people who know what they’re doing can sharpen knives with like a rock from the woods

Why would it be harder to keep them flat? Regardless of one-sided or two sided, you should be giving your stone a few passes with a flattener before sharpening.