Amazon.com: ADATA 1TB 2230 SSD, Legend 820, NVMe PCIe Gen4 x 4 M.2, R/W Speed up to 5,000/4,500MB/s, Internal Solid State Drive Great for Steam Deck, Microsoft Surface and Gaming Consoles. :
NEW 2230 SSD 1TB NVMe PCIe for Microsoft Surface Pro X 7+ 8 Surface Laptop 3 & 4 | eBay
This 2TB Micron M.2 2230 SSD is perfect for your Steam Deck, and it's £150 from Amazon | Eurogamer.net
WD PC SN740 512GB M.2 2230 SSD NVMe PCIe4x4 For Steam Deck ASUS ROG Ally Laptop | eBay
The Best SSDs for Steam Deck
The Best SSD for the Steam Deck in 2024: Fast NVMe Drives for Gaming on the Go | Tom's Hardware