I bought the new Samsung 980 Pro 1TB (PCIe 4.0) and put in the Lenovo Yoga Slim 7 (PCIe 3.0), I saw only ~10% decrease in raw performance : r/AMDLaptops
Samsung Ssd M.2 Nvme 250g 500g 1tb 970evo Plus 980 Pro Hard Drive Pcie 3.0x2 Hdd Hard Disk Solid State Pcie For Laptop - Solid State Drives - AliExpress
Samsung 980 Pro review | TechRadar
980 PRO PCIe® 4.0 NVMe™ SSD 1TB Memory & Storage - MZ-V8P1T0B/AM | Samsung US