KDE configurations modules can be launched with kcmshell5 which we ship in the kde-cli-tools package. There are some modules which are part of plasma (like kcm_colors for changing breeze color schemes) and there are others that are not, like kcm_sddm (kde-config-sddm package), kcm_printer_manager (print-manager module) and others.
It is interesting to explore this because kde-config-sddm and print-manager work very (and we don't ship and sddm config toll and the printer manager we ship is gtk) well and there might be others. We could ship them and do our own .desktops.
Besides that we could explore "detaching" some modules from plasma, like kcm_colors.

We could also ship systemsettings (KDE control panel) but I wouldn't recommend it. We corrently have in the system kcm modules for: filetypes, bluedevil, some web config and althought it's not listed with "kcmshell5 --list" breezestyleconfig which I'm not sure if it works ok.

Examples:

sudo apt install print-manager
kcmshell5 kcm_printer_manager

con sudo apt install kde-config-sddm
kcmshell5 kcm_sddm

here are plasma kcms code
https://phabricator.kde.org/source/plasma-desktop/browse/master/kcms/
https://github.com/feren-OS/plasma-desktop-kcms

I think "detaching" kcm_colors would be good
https://phabricator.kde.org/source/plasma-desktop/browse/master/kcms/colors/