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 980 PRO Heatsink 1TB Internal SSD PCIe Gen 4 x4 NVMe for PS5 MZ-V8P1T0CW - Best Buy
Samsung 980 Pro 2TB SSD review: high standards | Club386