I would agree that most restaurant sauerbratens are “meh” at best. But, the version my dad (and now my brother) made was just about my favorite dish growing up.
I wouldn’t think to look for German food in Arizona, but if you say it is that good, then I need to reconsider.
The interesting thing about that plum cake was that Johnny and Mariton didn’t like it nearly as much as I did. No problem, that just left more for me! Have fun and eat well at the German restaurant you are visiting.