Hi Ivan,
Thanks a lot for reading me and enjoying my articles. Glad to see this one connected particularly well with you.
Regarding Japanese, my first full-fledged book was 昔僕が死んだ家 by 東野圭吾. It wasn't very long nor was it very hard to read. The first 30-or so pages were quite difficult but the story was very easy to follow afterward. It could be worth a try.
Or, if you prefer reading manga first, I especially liked Hikaru No Go (although I didn't read it in Japanese. It could be hard to understand in Japanese)
For Korean, depending on your current level, you could try rewatching a K-drama you enjoyed and set subtitles to Korean only. This should help a lot. I still struggle to watch without Korean subtitles but that may be because I now try to understand as many details as possible.
For French, did you finish Assimil? If yes, I wouldn't be that surprised you could understand that much. That's what happened to me when I did the Chinese Assimil. If you want to slowly improve without taking time away from JPN and KOR, I'd say to set French as a second subtitle when you can, read FB postings, and practice writing or speaking with someone (I could potentially help with that if you're interested). You could also try reading things about Napoleon's life in French. Since it's a topic you enjoy, you'd probably be able to stick through struggles.
It could be interesting to chat on Zoom yes, let me reach out.
Thanks again for reading and commenting!