Peter, thank you for your answer. I am finding autosomal dna matches with other cousins having some of the same ancestry. These matches are not strong but have been useful to me. It’s true, the couple concerned have just a few descendants.
I do have matches with a few people having German family names but these are descendants of immigrants to Australia, USA etc. I don’t think I’ve ever matched with a German though I have matches with Swedes and Norwegians. One reason might be that few people in Germany take tests.