You need more space during the install than it will occupy when the
install is complete.
I think you have 2 options - make your target root larger, or install
fewer packages during the kickstart (install them after the kickstart
completes).
Also - note that if it is this tight on space during the install, you
are likely to run into a similar issue during a "dnf update" if there
are a large number of packages to update, as well as for any future
upgrade.
And a final comment - as it appears you are installing Fedora 37,
this
should really be asked on the test list. For one thing, over there
they might be aware of a larger minimum disk size that is required.
Thanks for the suggestions but I think it must be something more obscure - I gave up
trying to build a "minimum" iso with a view to adding stuff to it as needed and
just built the current standard KDE live USB - and that worked fine . . so now I will work
backwards and see what I can remove . .