No way to install KDE5 without deinstalling something already in your computer.
As the error message says, there are conflicting packages (
plasma[5|6]-layer-shell-qt-[5.27.11|6.1.2]
), and unfortunately, the conflict is mutual and unavoidable (the upstream KDE project seems to intend to be as such, no support for multiple versions of KDE on single computer at the same time).
You need to decide that
- preferring KDE5, allowing anything in your computer to be deinstalled,
- preferring existing environment, stop trying to install KDE5
For the option 2, you have another choice. Installing KDE6 instead of KDE5.
But KDE6 on FreeBSD does NOT YET have everything KDE5 already has.
If you prefer option 1, check for which packages are depending upon
plasma6-layer-shell-qt-6.1.2
recursively and deinstall all of them.
You can run
pkg query %rn plasma6-layer-shell-qt-6.1.2
to determine which packages depends
DIRECTLY upon it. Then,
recursively run the alike for found packages until nothing more appears.
If you don't mind installing some more ports, you can try
ports-mgmt/pkg_tree. It can show dependencies tree both forward and backward.