m.2 slot pcie - Suspended Domain
Similar to the PCIe expansion slots of your motherboard, the number of PCIe M.2 slots it will offer also depends on the number of PCIe lanes your motherboard supports.
Best B550 motherboards in 2024 - XDA
Despite its price tag, this B550 motherboard has all the necessities: four DDR4 RAM slots, two NVME slots, a couple of PCIe x16 slots with Gen 4 connectivity, support for ARGB, and more.
Mainboard MOBO H610M V2.02 DDR4 – Vương Luân Computer
I like the 4 nvme slots of the motherboard, and pcie5.0 slot, cause of the gpu that I own, but good mobo with pcie 4.0 are not a problem.