No one of that boot options seem to work in Devuan 2.

quiet vga=current
quiet gfxpayload=vga=current
quiet gfxpayload=vga=current loglevel=0

Are there some Usplash or Splashy packages installable in Devuan? Some in text mode?

https://dev1galaxy.org/viewtopic.php?pid=12356

I installed Devuan 2 + MATE, which defaults to Slim display manager.
To see users list at the graphic login interface, I needed to switch to LightDM, and it worked with only this command:

sudo apt-get install lightdm libpolkit-backend-elogind-1-0

(reboot and shutdown work)
Today I've edited /etc/pam.d/lightdm-greeter to replace the use of pam_systemd.so by pam_elogind.so , although I don't know what it is necessary for.

Devuan 2 needs some packages fix to allow a cleaner switch between Slim and LightDM:

• lightdm should deped on libpolkit-backend-elogind-1-0

• slim should deped on libpolkit-backend-consolekit-1-0

• task-mate-desktop should depend on any of libpolkit-backend-consolekit-1-0 | libpolkit-backend-elogind-1-0

Without this last fix, installing libpolkit-backend-elogind-1-0 it's also removed task-mate-desktop and some other packages are suggested for autoremoval: gnome-orca speech-dispatcher libreoffice-gtk3 etc.

Thank you; done (but with greeter-hide-users=false).
Shutdown action from desktop controls is not working now.