I am looking for novels with an OP military due to them being technologically advance. Like Gate and RtW with their modern weapons (or semi-modern? weapons for RtW) in a medieval world. Or like That Apocalypse Mansion with Future Technology in a Modern Setting. Also I am aware of the Technological Gap tag (just putting it there in case someone tells me to go look into those. I mean I could, but I'm too lazy to check each and every one of them.)
aa.. its not advance but try The Devectiv Hermit at Rrl. its apocalipse where advance tech/gun doesnt work. then the mc make it work again with magic.
Tensei Shitara Slime Datta Ken Well it got tanks, air ships ishh.. magics, war, soldiers. But most of them will appear in late chapters. SO you have to wait.