I got everything in the campaign, including every collectibles, assignments, etc etc.. Got Final Duty, Above and Beyond the Call and Peacemaker, but I still didn't unlock the full arsenal achievement.
I play on PC btw
I have this same problem and I reached out to EA/DICE and both said its a Playstation issue. I reached out to Playstation and they said it was developer issue. The normal blame game with no solutions offered. I did find this forum which might help. Good luck, sorry its such an issue for us with no solutions.
https://forum.psnprofiles.com/topic/124658-full-arsenal-bug-solved/
