I would like to recommend a free, multilingual, shared database for historians called
FactGrid, a joint initiative of German research centers. The platform runs on the versatile Wikibase (like Wikidata), the data can be used freely by anyone but can be edited only by historians. At the moment there are already 150,000 items in the
data set and it's constantly expanding with new projects and will have the full database of the German National Library integrated.
I hope you find it useful, let me know if you have any questions, and if you can, please share the information with other researchers.
Best wishes,
Adam Harangozó