Disclaimer: I did not remember how I got ksh installed, and all of this might be just historical mess in my setup updated by `dnf distro-sync` for years.
Anyway, let it be here for google which doesn't know these ksh-related errors at all. Feel free to close this ticket as invalid.

The problem is this:

  # rpm -e ksh
  /usr/bin/ksh93 has not been configured as an alternative for ksh
  error: %preun(ksh-3:1.0.3-1.fc37.x86_64) scriptlet failed, exit status 2
  error: ksh-3:1.0.3-1.fc37.x86_64: erase failed

And for this case following part of install scriptlet can't complete as well:

  # /usr/sbin/alternatives --install /usr/bin/ksh ksh /usr/bin/ksh93 50
  the primary link for ksh must be /bin/ksh

At the same time:

  # ll /usr/bin/ksh /usr/bin/ksh93 /etc/alternatives/ksh
  lrwxrwxrwx. 1 root root      10 Apr 12  2020 /etc/alternatives/ksh -> /bin/ksh93
  lrwxrwxrwx. 1 root root      21 Apr 12  2020 /usr/bin/ksh -> /etc/alternatives/ksh
  -rwxr-xr-x. 1 root root 1428368 Sep 19 13:54 /usr/bin/ksh93