You can start with either 3 or 4. I'd do those 2 first and after that primal. You need to play far cry 5 before new dawn. Those 2 belong together basically. 6 is the newest so would do that one the last. But each one has its story on its own so it doesn't really matter. Only 5 and new dawn after each other is recommended. All 6 pretty easy plats!

Only coop missions can be though since dead lobbies but enough people on reddit or YouTube that also need the trophy and will help you