Actually an anecdote on switching, my father in law bought an iPhone in a pawn shop. It was logged in with someone else’s iCloud account. He just used that until he dropped dead. We had no idea until I had to clean his phone out. My mother doesn’t even know what iCloud is. Literally total ignorance must be the default for everyone these days.

I’ve done the random switch thing as well as a test case. But to Microsoft. It took me a day to export all photos from Photos.app and into OneDrive and that was with a Mac (105Gb). And of course you lose all the edits you did if you export the originals.