Good article on the BFC HSC preseason game https://www.terraceedition.com/home-haute/the-berlin-derby-that-never-was-dynamo-hertha-damiano-benzoni-football-photography-groundhopping
lots of football in berlin
we stumbled across BFC Dynamo - the old Stasi club playing in an amazing stadium (Friedrich Ludwig Jahn Sportpark) when we visited the Mauerpark flea market. That was 7 years ago - don't think they play there anymore. Lots of lower-league options