@juergen_hubert@mementomori.social A few people went the roving adventurers after a war route before. HeXXen 1733 starts with the gates of hell opening during the 30 years war and diverges from there, using regional legends sometimes.
The 30 years war is also a pretty established setting in the OSR, I think Gazer Press did a few modules around it.
So it would not seem as something completely new going that way.

I would go Vormärz.