I harvested a PCIe Gen3 x2 NVMe 1.3 SSD from my older laptop, the problem is that its length is short. I've held it in place with some tape, it should hold.
Price history & Review on KingSpec M.2 ssd M2 240gb PCIe NVME 120GB 500GB 1TB Solid State Drive 2280 Internal Hard Disk hdd for Laptop Desktop MSI Asrock | AliExpress Seller -
KingSpec M2 SSD 1TB M.2 ssd 240GB 500GB PCIe NVMe SSD 2280 SSD 2242 hdd For Laptop Desktop Internal Hard Drive MSI xiaomi air|Internal Solid State Drives| - AliExpress
MSI Global - The Leading Brand in High-end Gaming & Professional Creation
Silicon Power 256GB - NVMe M.2 2280 PCIe Gen3 x4 TLC R/W up to 3,100/1,100 MB/s SSD (SP256GBP34A80M28) - Newegg.com
SPATIUM M370 NVMe M.2
The Best PCI Express NVMe Solid State Drives (SSDs) for 2022 | PCMag