Unless you're using a NUC or similar, M.2 is the worst form factor - and consumer grade drives are all shit. If you're in the market for storage I'd recommend looking at used enterprise U.2 drives in the 0.5-1 DWPD range. Adapters (PCIe or M.2 to U.2) are super cheap.
Edit: 12.8TB is gonna be a stretch, obviously, but even Solidigm TLC drives are quite a bit better than any consumer grade drives and I've seen some of the 7TB models go for surprisingly cheap.