kaos_user (kpm* or kmp*, I don't remember the exact name)
Please post the exact error, you can find it at /var/log/pacman.log
, look for the timestamp of that update and paste that section here (if you decide to post the full log, then please use a pastebin service like https://paste.ee/)
The real bug is that Calamares was still installed
A new Plasma 6 ISO is due, and will have that error corrected (Calamares and all it's depends should be removed in post-install, see the installation.log, same location as pacman.log, you will find that it tries to uninstall calamares instead of calamares6). Problem is Calamares fails to build on Qt 6.6.1, no answer yet how to fix, so no new ISO can be released.