No one up to iOS v14 or so ever asked me for help on using it or really fixing it. MacOS passed the grandma test for me and generally requires less user support. But iOS under jobs was a gold standard in usability.
I've found non tech users find MacOS far less intuitive honestly. I do think the Windows paradigm is probably the most intuitive, with a startbar launcher and apps being clearly separated in the taskbar and not grouped together under a bouncing icon.