Does the PCIe x1 m.2 adapter work? Yes, but there are some downsides.
GLOTRENDS M.2 PCIe X1 Adapter with M.2 Screw for M.2 PCIe 4.0/3.0 SSD (NVMe/AHCI Key M), PCIe X1/X4/X8/X16 Lane Installation, but Only PCIe X1 Bandwidth (PA09-X1) : Amazon.ca: Electronics
What are PCIe x1 Slots Used For? | 8 PCIe Devices for x1 Slots - YouTube
The Primer: PCI Express 1.0 vs. 2.0 - 6Gbps SATA Performance: AMD 890GX vs. Intel X58/P55
Difference Between PCI Express Gen 1, Gen 2, Gen 3, & Gen 4 – DESKDECODE.COM
PCIe X1 to 2-ch M.2 SATA 6Gbps Expander, JMB582 control chip | PCIe -SATA-M2-2P-A
GLOTRENDS M.2 PCIe X1 Adapter with M.2 Screw for M.2 PCIe 4.0/3.0 SSD (NVMe/AHCI Key M), PCIe X1/X4/X8/X16 Lane Installation, but Only PCIe X1 Bandwidth (PA09-X1) Add-On Cards - Newegg.com
Introduction to PCI Express (withdrawn product) > Lenovo Press
Difference between PCI Express X1 & X16 and between 2.0 & 3.0 – HeelpBook