HP Laptop (HP pavilion 15 ck018nl) and NVME specs

I have this laptop and I'd like to replace it's 120GiB M2 SATA with an NVMe one but I can't find the specs of the slot, could please someone help me, the motherboard is the HP841C (yes, it has the same name as a printr from the early '00). For what I know it supports the NVMe M2 and also the SATA over M2 but It's not clear what version of NVMe. Could someone help me telling how to figure it out?

Thanks

EDIT: My issue is: should I get pcie gen4, pcie gen3 or pcie gen2, is the slot on the board type B or type M (I've not yet opened the machine), are the slot x2 or x4?

Your model supports these Solid State Drives drives

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