Replacing RAM, NAND storage chips on recent Apple products
(I don’t think this includes the “unified memory” in the newest, Apple Silicon, machines.) The onboard RAM and storage chips, soldered to the logic board in, e.g., the MacBook Air machines since forever, actually can be upgraded by the end user ... If the end user has access to a hot air rework station (like the X-Tronic 6020-PRO-X , or the 6040-PRO-X if you also need a soldering iron) and the skill to use it! As seen here (and many places): https://www.youtube.com/watch?v=UIsMx28Pakg MacBook Air logic board showing RAM chips