I cant “upgrade” the pcie ssd, there is none, only a sata ssd. Ive taken apart a half dozen imacs and they are not that difficult to work on. You have to take EVERYTHING out . everything consists of a lcd panel, hard drive, a fan a power supply and speakers a bunch of screws and a few ribbon cables. Apple can change its proprietary connection every year if they like but most understand its just their version of m.2 in this case pcie m.2
