Well, that's the thing. RAM is still way faster. My gen3 machine I upped from 550 mb/s 2.5" SSD to 3,000mb/s+ nvme, (gen 4 nvme is 7,000mb/s+). But look at RAM speed by comparison.
DDR4 data transfer rates:
DDR4 2133: 17,000mb/s
DDR4 2400: 19,200mb/s
DDR4 2666: 21,300mb/s
DDR4 3200: 25,600mb/s...