BEWARE: Lenovo Thinkpad L15 Gen3 SSD is practically un-upgradeable. Laptop comes with 256GB and bigger SSD is too thick to fit. There also goes a cooling plate on top. : r/thinkpad
63Y1755 63Y2086 For Lenovo Thinkpad X201 TABLET X201T laptop mainboard With CPU i7-640LM With Fan heatsink /Wlan Upgrade X200T _ - AliExpress Mobile
Tutorial: How to upgrade the ram in a Lenovo x201 Laptop (in 1080P) - YouTube