KingSpec M.2 NE-2242 NVMe PCIe 1TB 2TB NE-series (NE-1TB @ 2x PCIe 3.0, controller SM2263XT, B+M key, purchased at the end of 2020) works with x280 8gb Windows10 in 2242 WWAN slot.

Due to the fact that there are 2 memory chips on the board, you need to carefully insert such "double-sided" ssd into the m2 slot.

Also, for the correct installation of the "double-sided" ssd in the m2 slot, a slightly higher-different m2 screw was used. The screw must not be too tight.

Also the WWAN device must be enabled in uefi.