Uhh no.
Zen is Gen 1, pcie 3.0
Zen+ is Gen 2, pcie 3.0
Zen 2 is Gen 3, pcie 4.0
Zen 3 is Gen 4, pcie 4.0
How much pcie depends entirely on the motherboard chipset. There's a big difference between an X570 pcie 4.0 capability and a B550 pcie 4.0 capability.
X570 have 24 pcie 4.0 lanes coming from the cpu. 16x are used for the gpu, 4x for a m.2 and a pcie 4 x4 goes to the chipset. The chipset has pcie 4.0 x16 but they are used in a configuration determined by the motherboard manufacturer.
B550 has 20 pcie 4.0. It uses x16 for a gpu and 4x for an m.2 but the chipset only has pcie 3.0 x4 .The 3.0 x4 pcie lanes either go to a 2nd m.2 or a bottom pcie slot.
So doesn't matter if you stick a 5950x or 3700x in a B550, you still only get 1x Gen4 NVMe at pcie 4.0, any other M.2 slots are stuck for Gen3, pcie 3.0 NVMe. You'd need an X570 to use 2 or more Gen4 NVMe drives at pcie 4.0
X470 are pcie 3.0 and on down becomes a mix of pcie 3.0 and pcie 2.0