Do you miss "Fullmetal Alchemist"? If so, I recommend giving "Youjo Senki" a try. Why do I say this? Keep on reading. Both series' have a very similar vibe where the setting of the story is loosely based off history, and takes place during a time of devastating war. "Youjo Senki" and FMA share almost the same vibes due to the focus and the point of view that its told from; with "Youjo Senki" focusing even more on the events and the historical implication of those events, and FMA focusing more on the "magic". "Youjo Senki" is more like a documentary. "Youjo Senki" is also a isekaistory, but unlike alot of the ones that are coming out nowadays; it's much more enjoyable for a older audience. It has a lot of the classic isekai aspects like an OP MC winning all battles with information from the other world, or having some sort of attribute or ability granted to them for the purpose of making them special in their new world. In addition to being a well told serious story, the author finds appropriate places to inject some humor and it meshes nicely without disrupting the flow of the story.

Just like how FMA became a classic must read/watch, I think "Youjo Senki" will become one too, and I hope that you will give this series a read.