SUMMARY
After every logout and every boot, Plasma Login Manager keeps choosing the Dvorak layout, which is my default, but instead it should remember the last used keyboard layout so my family can quickly hop in without mistyping the password due to the default-forced layout.

STEPS TO REPRODUCE
1. Have multiple layouts defined in xorg.conf.d/*-keyboard.conf and have one non-QWERTY default:

$ » cat /etc/X11/xorg.conf.d/00-keyboard.conf      
Section "InputClass"
        Identifier "system-keyboard"
        MatchIsKeyboard "on"
        Option "XkbLayout" "latam,latam"
        Option "XkbModel" "pc104"
        Option "XkbVariant" "dvorak,deadtilde"
        Option "XkbOptions" "grp:win_space_toggle"
EndSection

2. After booting up PLM, change the layout via the bottom left corner
3. Log in and then log out

OBSERVED RESULT
The layout gets reset to whatever /etc/X11/xorg.conf.d/*-keyboard.conf has defined

EXPECTED RESULT
PLM should remember the last used keyboard layout by default and make this behavior toggleable via its KCM

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
(available in the Info Center app, or by running `kinfo` in a terminal window)
Linux/KDE Plasma: Arch Linux
KDE Plasma Version: Git Master as of now
KDE Frameworks Version: Git Master as of now
Qt Version: Git Master as of now

ADDITIONAL INFORMATION