Weapons that were released during the game's "Tides of War" live service chapters are no longer earnable through weekly challenges. Instead, you can buy them directly: Go to from the main menu. Select the Class and the primary weapon slot.
(unless EA re-releases them):
The beauty of Battlefield V is that the (The Sten for Medic, the KE7 for Support are top-tier). Unlocking every weapon dilutes your muscle memory. However, if you are a completionist or a competitive player who needs the Zk-383 (Medic Rank 20) or the FG-42 (Support Rank 20), you need to grind or pay. battlefield v unlock all weapons