Login screen for F40

[Michael Eager]

I recently upgraded to F40 (KDE) and, for the most part, everything is 
working.  Except the login screen.

I've tried to install slick-greeter and lightdm-gtk-greeter, following 
whatever recommendations I found online.  The result is a hung system 
with a black screen until I remove the greeter configuration and reboot.

Can someone point me to a reasonable login screen and configuration?