Andy's review is here -

https://www.andyhayler.com/restaurant/schwarzwaldstube

Personally I pay absolutely no attention to the Pellegrino list. (Neither does Andy.)

I've not been to Tonbach. However, I did once stay four nights at nearby Bareiss and regard that as the best hotel for food I have ever stayed at. I think the two hotels are rather similar in terms of their dated accommodation and outstanding spa facilities.