I use openSUSE Tumbleweed and I noticed that the new Virtual Keyboard for the login screen (button on the lower left corner of the screen) is only available when the user is already logged in and the session is locked. When the user is not logged in (e.g. computer has just booted into login screen) the Virtual Keyboard button is not visible.
This is an SDDM issue, which is tracked elsewhere: https://github.com/sddm/sddm/issues/100