What a coincidence, but today I ran into a very similar, if not exactly the same issue. Luckily on a throwaway testing system, but still very annoying.
I made a fresh install of Antix-17.4. I changed the repos from stable to testing. Here's part of my debian.list
# Use for maximum stability INSTEAD of the 'rolling' TESTING release concept.
#deb http://ftp.be.debian.org/debian/ stretch main contrib non-free
#deb http://security.debian.org/ stretch/updates main contrib non-free
#deb-src http://ftp.be.debian.org/debian/ stretch main contrib non-free
# Debian Testing.
# Testing enabled for 'rolling' release.
deb http://ftp.be.debian.org/debian/ testing main contrib non-free
#deb http://security.debian.org/ testing/updates main contrib non-free
deb http://security.debian.org/ testing-security main contrib non-free
#deb-src http://ftp.be.debian.org/debian/ testing main contrib non-free
Note that the nosystemd flag is missing, which I didn't notice at the time. Why is it that a new installation has a wrong debian.list???
Everything went well, untill I decided to install SMPlayer with the metapackage installer. Here's part of the apt log file. If I understand it correctly,
that's where my xorg installation gets wiped out. Next time I logged out, I couldn't get back in... :-(
Start-Date: 2020-07-01 13:50:43
Commandline: apt-get install --reinstall smplayer smplayer-themes
Requested-By: dd (1000)
Install: libwayland-egl1:amd64 (1.18.0-1, automatic), libegl1:amd64 (1.3.1-1, automatic), libegl-mesa0:amd64 (20.1.2-1, automatic), gcc-10-base:amd64 (10.1.0-4, automatic), libgl1:amd64 (1.3.1-1, automatic), libicu67:amd64 (67.1-2, automatic), libgles2:amd64 (1.3.1-1, automatic), smplayer:amd64 (19.10.2~ds0-1), libcrypt1:amd64 (1:4.4.16-1, automatic), smplayer-themes:amd64 (1:18.6.0-1), libcrypt-dev:amd64 (1:4.4.16-1, automatic), libglx0:amd64 (1.3.1-1, automatic), qt5-style-plugin-cleanlooks:amd64 (5.0.0+git23.g335dbec-3+b3, automatic), qt5-gtk2-platformtheme:amd64 (5.0.0+git23.g335dbec-3+b3, automatic), libgcc-s1:amd64 (10.1.0-4, automatic), libqt5gui5-gles:amd64 (5.12.5+dfsg-2, automatic), libffi7:amd64 (3.3-4, automatic), qt5-style-plugin-plastique:amd64 (5.0.0+git23.g335dbec-3+b3, automatic), qt5-style-plugin-motif:amd64 (5.0.0+git23.g335dbec-3+b3, automatic), libxcb-xinput0:amd64 (1.14-2, automatic), libpcre2-16-0:amd64 (10.34-7, automatic), libdouble-conversion3:amd64 (3.1.5-5, automatic), libglx-mesa0:amd64 (20.1.2-1, automatic), libglvnd0:amd64 (1.3.1-1, automatic), libdrm-common:amd64 (2.4.102-1, automatic)
Upgrade: qt5-style-plugins:amd64 (5.0.0+git16.g7aa4764-1, 5.0.0+git23.g335dbec-3+b3), libqt5svg5:amd64 (5.7.1~20161021-2+b2, 5.12.5-2), xserver-common:amd64 (2:1.19.2-1.0nosystemd5, 2:1.20.8-2), libwacom-common:amd64 (0.22-1, 1.3-2), qt5-gtk-platformtheme:amd64 (5.7.1+dfsg-3+deb9u1, 5.12.5+dfsg-10+b1), libc6-dev:amd64 (2.24-11+deb9u4, 2.30-8), virtualbox-guest-utils:amd64 (5.2.24-dfsg-4~mx17+1, 6.1.6-dfsg-2~mx19+1), libglapi-mesa:amd64 (13.0.6-1+b2, 20.1.2-1), libqt5dbus5:amd64 (5.7.1+dfsg-3+deb9u1, 5.12.5+dfsg-10+b1), libc6:amd64 (2.24-11+deb9u4, 2.30-8), libqt5widgets5:amd64 (5.7.1+dfsg-3+deb9u1, 5.12.5+dfsg-10+b1), locales:amd64 (2.24-11+deb9u4, 2.30-8), libegl1-mesa:amd64 (13.0.6-1+b2, 20.1.2-1), libepoxy0:amd64 (1.3.1-2, 1.5.4-1), firetools:amd64 (0.9.58-1.0antix1, 0.9.62-1), fontconfig-config:amd64 (2.11.0-6.7, 2.13.1-4.2), control-centre-antix:amd64 (0.6.21, 0.7.23), luckybackup:amd64 (0.4.9-1, 0.5.0-3), libqt5xml5:amd64 (5.7.1+dfsg-3+deb9u1, 5.12.5+dfsg-10+b1), libgbm1:amd64 (13.0.6-1+b2, 20.1.2-1), libqt5printsupport5:amd64 (5.7.1+dfsg-3+deb9u1, 5.12.5+dfsg-10+b1), libqt5qml5:amd64 (5.7.1-2+b2, 5.12.5-5), libwayland-client0:amd64 (1.12.0-1+deb9u1, 1.18.0-1), libinput-bin:amd64 (1.6.3-1, 1.15.5-1), libc-l10n:amd64 (2.24-11+deb9u4, 2.30-8), libc-bin:amd64 (2.24-11+deb9u4, 2.30-8), qt5ct:amd64 (0.33-1mx17+1, 1.0-1), libwayland-egl1-mesa:amd64 (13.0.6-1+b2, 20.1.2-1), libgcrypt20:amd64 (1.7.6-2+deb9u3, 1.8.5-5), libqt5script5:amd64 (5.7.1~20161021+dfsg-2, 5.12.5+dfsg-2), libdrm2:amd64 (2.4.74-1, 2.4.102-1), libqt5core5a:amd64 (5.7.1+dfsg-3+deb9u1, 5.12.5+dfsg-10+b1), libfontconfig1:amd64 (2.11.0-6.7+b1, 2.13.1-4.2), libc-dev-bin:amd64 (2.24-11+deb9u4, 2.30-8), libwacom2:amd64 (0.22-1+b1, 1.3-2), libfreetype6:amd64 (2.6.3-3.2, 2.10.1-2), libxvmc1:amd64 (2:1.0.10-1, 2:1.0.12-2), libharfbuzz0b:amd64 (1.4.2-1, 2.6.4-1+b1), libqt5network5:amd64 (5.7.1+dfsg-3+deb9u1, 5.12.5+dfsg-10+b1), libstdc++6:amd64 (6.3.0-18+deb9u1, 10.1.0-4), wpagui:amd64 (2:2.4-1.0nosystemd2, 2:2.9.0-13), luckybackup-data:amd64 (0.4.9-1, 0.5.0-3), libxcb-dri3-0:amd64 (1.12-3, 1.14-2), libwayland-server0:amd64 (1.12.0-1+deb9u1, 1.18.0-1), libqt5sql5:amd64 (5.7.1+dfsg-3+deb9u1, 5.12.5+dfsg-10+b1), libx11-xcb1:amd64 (2:1.6.4-3+deb9u1, 2:1.6.9-2+b1), libinput10:amd64 (1.6.3-1, 1.15.5-1)
Remove: xserver-xorg-input-all:amd64 (1:7.7+19), xserver-xorg-input-synaptics:amd64 (1.9.0-1+b1), xserver-xorg:amd64 (1:7.7+19), xserver-xorg-video-r128:amd64 (6.10.2-1), xserver-xorg-video-siliconmotion:amd64 (1:1.7.9-2), xserver-xorg-video-qxl:amd64 (0.1.4+20161126git4d7160c-1), xserver-xorg-video-vesa:amd64 (1:2.3.4-1+b2), xserver-xorg-video-nouveau:amd64 (1:1.0.13-3), xserver-xorg-video-amdgpu:amd64 (1.2.0-1+b1), live-usb-maker-gui-antix:amd64 (0.1.10), antix-viewer:amd64 (0.1.2), xserver-xorg-input-elographics:amd64 (1:1.4.1-1+b5), xserver-xorg-core:amd64 (2:1.19.2-1.0nosystemd5), xserver-xorg-input-aiptek:amd64 (1:1.4.1-2+b1), xserver-xorg-video-cirrus:amd64 (1:1.5.3-1+b2), xserver-xorg-input-kbd:amd64 (1:1.9.0-1+b1), bootrepair-antix:amd64 (17.10), xserver-xorg-video-trident:amd64 (1:1.3.8-1), xserver-xorg-video-fbdev:amd64 (1:0.4.4-1+b5), installer-data-antix:amd64 (0.1.8), xserver-xorg-input-libinput:amd64 (0.23.0-2), xserver-xorg-video-savage:amd64 (1:2.3.9-1), xserver-xorg-input-wacom:amd64 (0.34.0-1), xserver-xorg-input-mtrack:amd64 (0.3.1-1+b2), codecs-antix:amd64 (16.22), xserver-xorg-input-joystick:amd64 (1:1.6.3-1+b1), packageinstaller:amd64 (0.1.8), antix-installer:amd64 (1.0.4.12), libqt5gui5:amd64 (5.7.1+dfsg-3+deb9u1), xserver-xorg-video-mach64:amd64 (6.9.5-1+b2), network-assistant:amd64 (0.1.2), xserver-xorg-video-sisusb:amd64 (1:0.9.7-1), xserver-xorg-video-intel:amd64 (2:2.99.917+git20161206-1), xserver-xorg-video-tdfx:amd64 (1:1.4.7-1), libqt5webkit5:amd64 (5.7.1+dfsg-1), smtube:amd64 (18.11.0-0.1~mx17+1), xserver-xorg-video-vmware:amd64 (1:13.2.1-1+b1), xserver-xorg-input-evdev:amd64 (1:2.10.5-1), xserver-xorg-video-all:amd64 (1:7.7+19), xserver-xorg-video-ati:amd64 (1:7.8.0-1+b1), libqt5opengl5:amd64 (5.7.1+dfsg-3+deb9u1), libgl1-mesa-glx:amd64 (13.0.6-1+b2), xserver-xorg-video-radeon:amd64 (1:7.8.0-1+b1), xserver-xorg-video-neomagic:amd64 (1:1.2.9-1+b2), antix-user:amd64 (0.1.4), repo-manager:amd64 (0.1.17), libqt5quick5:amd64 (5.7.1-2+b2), xserver-xorg-video-mga:amd64 (1:1.6.5-1), virtualbox-guest-x11:amd64 (5.2.24-dfsg-4~mx17+1), xserver-xorg-video-glide:amd64 (1.2.2-1+b6), xserver-xorg-video-openchrome:amd64 (1:0.5.0-3)
End-Date: 2020-07-01 14:04:12
Quite unrelated, but maybe someone can help me with that too. Somewhere along the way the icons in Control Centre change from the very nice Faenza type (which is supposedly the default for Antix17) to the downright horrible Papyrus. It's not that important, but if possible, I would like to avoid it.