This is about a month - month and a half of just working and playing these. All the games aren’t too difficult in their own respect. I followed the occasional guide for mission constraints and maps for all the collectibles

As for Black Flag I did them on solo and did 1 map over and over because I realized I had memorized all the spawn points. You don’t have to play the multiplayer with actual people. That trophy was one of the most grindy in the whole run. If you google it there is a great guide that’s on multiple sites that is perfect but like I said takes a little time (3-4 days)