PCIe x4 SSD and PCIe x4 slot

I believe both slots are generation 3 because chapter 1 of the manual indicates that HP only offered Gen 3 NVMe SSD's in the model series and

x16, 1 PCIe x16, 1 PCIe x1, 1 Key E for Besides the onboard LAN port, users may also choose wireless connections by slot

m2 expansion slot Due to the forward and backward compatibility, a PCIe GPU will perform like a PCIe GPU card if connected to a PCIe (or in the future

m2 slot mainboard USB Gen 2 x 2, USB Gen 1 x 4, USB x 3 (Optional Mini PCIe Slot x 1 Micro SIM Card Slot x 1