Make sure to merge the /etc/sddm.conf.pacnew, since session naming for example has changed (there was supposed to be a pop-up with this info for the plasma 6 move, but somehow some users don't get it). There should not be a change in HideUsers behavior.

    demm thanks I'll see it tonight, I've also had this concern in ArcoLinux for several months, if I put my user in HideUsers I don't have an area for inputting my username in sddm.

      Ah, this is not new? Then the new sddm 2.0/QML changes are probably to blame. What sddm themes have you tried? Same issue with the breeze theme?

        demm I will try breeze theme to see what happens to sddm, when coming home in some hours thanks.

          demm yes you were right, if I use an other sddm theme than breeze I can't access to the user login zone ! thanks for your help.

            No, that is a bug in the other themes, so you have the same issue with the Midna theme? That will need fixing then.

              Can you please also test with the default sddm theme, Maui? Just leave the theme empty in the conf file, it will always fall back to that default.

                demm same bug with default theme, unable to get access to login if HideUsers is set.

                  Not solved at all, they just closed it without addressing the fact that the default theme shipped in SDDM fails.

                    demm proposed workaround : "use a sddm theme which is doing the required job and good bye"