Chris Murphy wrote:
... If the change is approved, I'll suggest Docs team revise
documentation to recommend any resize of the pre-installed OS (macOS
or Windows) be done within those operating systems using their tools.
Right now, there's no support for resizing any macOS file system
layout anyway, so we have to advise the user accordingly anyway.
When I do this (at least every Fedora release) I use gparted (via a
LiveUSB if necessary) to produce the physical partitions that I want,
then use the Manual partitioning dialog to choose and assign them.