I would make my podcast on early modern warfare. this is because I am interested in the topic and have a decent amount of knowledge on the topic. I think this would work since Early Modern combat is really interesting and their are many wars to talk about. further with major conflicts like the 30 years war, the wars of Louis XIV, and the seven years war there would be plenty of conflicts people know to talk about. further this time period saw rapid changes in military technology which means that discussing changes in weaponry, tactics, and war planning becomes possible,