I know travel vloggers are very public about filming and editing as they travel, writers and bloggers. My godddaughter travels and works in so many countries. She misses it since covid.

Anyway, back to the question at hand. I would pick a country that you can take a train to many places. Budget is a big deal for a month. I really liked Lille and Reims. But if winter Spain would be on my short list. Andalusia/Cadiz. Have fun planning.