Dunno if you’re German or Austrian or something, but in Vienna there is a Ziegelmuseum whose curator studies the history of bricks, how they were made and used and whatnot. They have a long list of brick makers in Austria, when they were active and so on.
If you’re in another country, they could maybe help get you in contact with a historian local to you.
Could help you learn more about your mystery brick.
Ahmet has English subtitles on many videos, so check out one of his recipes. Turkish man living in Germany, an absolute dad. Makes good food and cracks corny jokes while doing it.