We would like recommendations for a private or small group tour guide for Munich the end of August.
Try Dark History. Taff Simon is Welsh, a trained archeologist and specializes in the unique history of Munich. We also toured Regensburg and Dachau with him. He has had extensive contacts with liberators and survivors of Dachau
https://darkhistorytours.com/
If you want a group tour, I found Radius to be a great tour guide. I took there Munich and Beer and Brewery tours.
As for Dachau, I will always recommend do it yourself and boing the 4euro official tour. It is so easy to get to Dachau via train and then bus. And our official tour guide actually met and talked with some of the Soviet POWs liberated.