Id say most of the starting guns are fine. I struggled with the Lewis Gun but the rest are fine.
Work towards war bonds and going through the levels of your prefered class. I always start as medic on games, gives me chance to re-heal and stay alive a little longer. Use each gun to its strenghs...
Are you on the PS4? I got myself into the top 3% in the World at one point. So I can talk you though it.
First if you are coming from CoD pick a game mode like Domination, smaller maps and get used to what guns and each class can do.
Once you have your class you need to pick the right gun. I...
Battlefront 2 should be a decent game.
I would avoid COD personally and pick up BF1.
Sonic Mania if you like retro games you can get this on the PS store, easily one of my favoruite games I have played in a long time.