Yesterday, SK hynix has finally unleashed its first Gen 4.0 SSD with a 176-NAND layer, namely the Platinum P41. As unveiled back in early January, it is available in 500 GB, 1 TB, and 2 TB versions. The prices start at US$104.99 and go up to US$259.98, but the stock seems depleted already.
https://www.notebookcheck.net/The-SK-hynix-Platinum-P41-flagship-PCIe-NVMe-SSD-hits-Amazon.621167.0.html