Our 2008 Miele was 1/2 inch slimmer than the 2000 Bosch it replaced. Thankfully, a couple of solid maple strips on both sides which I stained to match the cabinets fixed the problem. In 2017, replaced a Whirlpool with a Miele… same size. If your dw cavity was made for a skinnier one, then you would have a problem.
Bosch and many other dw are made to last 7-8 years. I would not spend $1000 to fix an old dw ($590 parts, plus $300 or so labor, I assume, plus tax). I would put that money towards a new Miele. At the fancy store, we were told that lower end appliances are hard to come by and take forever, but a $10K Subzero could be had within a week. I suspect a $3K dw might be in stock. Good luck with your search.