Can I Use a PCIe 4.0 Graphics Card in a PCIe 3.0 Slot? - TechReviewer
You can use a PCIe 4.0 SSD in a PCIe 5.0 slot, and it will work just fine, at PCIe 4.0 speeds. Similarly, a PCIe 5.0 SSD can be used in a PCIe 4.0 slot, but again, its performance will be limited to PCIe 4.0 levels.
PCIe 5.0: Khai thác sức mạnh của truyền dữ liệu tốc độ cao
AMD’s PCIe 5.0 controller has more PCIe lanes available, though, which is why AMD Ryzen 7000 processors are able to support both a PCIe 5.0 x16 slot for graphics cards and a PCIe 5.0 NVMe M.2 slot for SSDs.
Hướng dẫn về các loại SSD M.2, giao thức và cấu hình khóa
The main reason for this issue is that some M.2 slots on motherboards only support SATA M.2 drives, not NVMe, which are needed for higher PCIe SSD speeds.