here in Italy whatsapp is the most used, there are very few people who use telegram just to chat, we usually use it for piracy, or for the bots...
also I don't know a single person who use signal, and discord is mainly used by gamers for voice calls
I think persona 5 (if you can get the "royale" version) is the best to start playing persona, you don't need to play the previous one to enjoy that game
try going in the Lemmy settings and select your language, but note that most of the post is marked as "undefined" so it probably won't make a big difference
try installing the website as a native app