M.2 and OS/2

The M.2 is just a form factor port for different kinds of computer interfaces. The implementation of the interface will depend on the hardware. There are mainboards that support M.2 for SATA, other for NVMe (PCI express, PCIe) and some other support both.
SATA
There are reports of having a M.2 SATA SSD drives working on OS/2 Warp and ArcaOS.
The WD Blue 3D NAND SATA SDD M.2 2280 (1TB) was reported to be working on a Thinkpad Thinkpad 25. It works connected to the M.2 NVMe port, but please remember that not all M.2 NVMe ports have SATA compatibility.
NVMe
NVMe is currently in beta state for SSD devices on OS/2 or ArcaOS 5.1 (2022-07-03). The intentions of developing a driver from Arca Noae had been shared at Warpstock Europe 2019, and a driver had been produced by Arca Noae and it currently available in a close beta for ArcaOS 5.1. [1].
Some M.2 NVMe have SATA compatibility, so an M.2 SATA card can be connected and will work on OS/2, but it is not common for all NVMe adapters.
Read more about NVMe at Wikipedia.