Deutsche Nationalbibliothek appears to have 43.2 million "items", of which apparently 17.3 million are books. If we assume ~60,000 tokens for an average book, which seems very conservative given average word length in German and a novel typically being considered anything above ~40k words), that's another trillion just for their books, so I'm guessing the total German language content available in major libraries will be many times that.
E.g. the Norwegian National Library has somewhere between 3x and 10x as many tokens in Norwegian newspapers as in books (at one point I think GPT3 breakdown of training data by language surfaced, and the Norwegian data was a tiny fraction of what was available in the national library, even before trying to estimate online/digital content).
While I'm sure there's overlap [1] between the languages, a lot of it will help translation, and I think even for smaller languages the ratio of local content seems to dwarf translations. E.g. the "bestsellers" from English, French, and German all get translated to Norwegian, but most of the "long tail" content is local.
[1] I was tickled to a find one of my uncles represented in Deutsche Nationalbibliothek; he was a professor in statistics, so it was a translation of some of his research