From their repo:
Plasma Login
Plasma Login provides a display manager for KDE Plasma, forked from SDDM and with an new frontend providing a greeter, wallpaper plugin integration and System Settings module (KCM).
What we want
- Great out-of-box experience in multi-monitor and high DPI and HDR
- Keyboard layout switching
- Virtual keyboards
- Easy Chinese/Japanese/Korean/Vietnamese (CJK) input
- Screen readers for blind people (which then means volume control)
- Remote (VNC/RDP) support from startup
- Deeper Plasma integration including:
- Display and keyboard brightness control
- Full power management
- Pairing trusted bluetooth devices
- Login to known Wi-Fi for remote LDAP
It always chooses the default highest resolution, (which may not work on some devices with faulty EDID), does not respect the Wayland/X11 choice, has a long pause when going from login screen to desktop and does not support 24h clocks.
Just to name a few.
The first one I think is a fundamental limitation in that display preferences by default is per-user. Maybe this makes it work for you? https://feddit.online/post/1350756/comment/6636228
The 24h clock might be similar - check your system-wide locale.
Yea I have noticed this. It takes a long time to switch back as well when you lock the computer, logout, switch users, etc