I understand that to get a working VNC server, SDDM cannot be used, and “you need to switch to a different display manager”.
Could anyone suggest an alternative and perhaps a guide to how to do it?
Or alternatively, is there another tool I could use for this purpose (I need to be able to view other desktops to provide support to existing users, so RDP isn’t an option).
I use RealVNC, which allows for up to 5 remotes on their free license. It run under SDDM, the default Tumbleweed/KDE setup. VNC should work with SDDM/KDE with the standard VNC packages as well, provided you are using X11. I haven’t found any VNC/Wayland packages.
It is not in 15.5 - you can get it here: https://downloads.nomachine.com/download/?id=6 download and install the rpm
go to the download directory and
zypper in nomachine_8.9.1_1_x86_64.rpm