TL;DR, issue fixed by Xorg uprade. As Joan Figueras mentioned earlier, with the changes: xorg-server-common (21.1.1-2 -> 21.1.1-3) xorg-server (21.1.1-2 -> 21.1.1-3) xorg-server-xvfb (21.1.1-2 -> 21.1.1-3) Arch reverted the DPI Xorg behavior. He also shared the Arch defect filed for the issue [1], and from it, you can get to upstream Xorg issue [2], and the comment in there from the developer about the reversal [3]. Though I'm also keeping an eye on that issue, since there are comments suggesting Qt could improve in the way they read, interpret, and make use of the values provided by Xorg, although the dev. sounded pretty convinced is not the time to do it at this late stage of Xorg... All this just in case some were not aware about what happened, and get surprised of finding no issues at all, and then get confused about this thread... -- Javier [1] https://bugs.archlinux.org/task/72661 [2] https://gitlab.freedesktop.org/xorg/xserver/-/issues/1241 [3] https://gitlab.freedesktop.org/xorg/xserver/-/issues/1241#note_1153655