It sounds like everything is working as intended: Disease and Artillery are the two new ground weapons in Campaign 2 (for a total of 12 weapons across both campaigns), plus you should also have two new ship weapons, Vortex and Turret Energizer.
You seem to have all 12 ground weapons available, let me know if I’ve misunderstood and some are inaccessible.
No problem. The unlocks are rarer in Campaign 2 – it gets tricky to design and implement new weapons that are both useful and meaningfully different from existing ones, that won’t also throw off the balance of the base campaign