I use QEMU on Proxmox to create virtual machines, and for me, Lubuntu (23.10) is one of only a handful of distro’s where dynamic screen resolution works perfectly. I use SPICE (qxl) as my display device and I view the client with Virt-Viewer on a Win11 machine. I saw this thread and thought I would comment because I’m looking around to see if I can find out if Lubuntu has software in place that allows this to work. None of the major KDE based distros work (for me). I can set the correct resolution manually with xrandr, but if I change the size of the viewing window it does not adapt the resolution. I get borders on the viewing window and sometimes an incorrectly scaled display. Zorin OS 17 also works correctly. Strange since both KDE and LXQT are based on Qt yet KDE does not work in this environment. If you know anything about software within LXQT that enables dynamic resolution in VM’s, please advise.
There is nothing I know of that Lubuntu has in place that is unique relative to other official Ubuntu flavors. I would expect Kubuntu to work just as well in this regard.
Indeed, in VirtualBox, both work great.