After the most recent updates, booting goes to a black screen with the cursor.
I was able to get to TTY, and the only thing I found that partially resolved the issue was removing the nvidia proprietary drivers (nvidia-glx-driver-current, nvidia-glx-driver-common). Though I'd prefer to be able to use the proprietary drivers as the performance is better.
I've tried using the 470 versions of the drivers, re-installing the drivers, re-installing kwin.
Looking in the journal, there are a few things that I see failed to start or had warnings/errors, I'm not sure if any of these are related:
Dec 12 18:11:36 solus /usr/lib64/xdg-desktop-portal/xdg-desktop-portal[1241]: Choosing gtk.portal for org.freedesktop.impl.portal.Lockdown as a last-resort fallback
Dec 12 18:11:36 solus kwin_wayland[1231]: No backend specified, automatically choosing drm
Dec 12 18:11:38 solus kwin_wayland[1231]: drmSetClientCap for Atomic Mode Setting failed. Using legacy mode on GPU "/dev/dri/card0"
Dec 12 18:11:39 solus systemd[1178]: Started pipewire.service - PipeWire Multimedia Service.
Dec 12 18:11:39 solus systemd[1178]: Started wireplumber.service - Multimedia Service Session Manager.
Dec 12 18:11:39 solus kwin_wayland[1231]: KPackageStructure of KPluginMetaData(pluginId:"alwaysopenonprimaryscreen", fileName: "/home/user/.local/share/kwin/scripts/alwaysopenonprimaryscreen/metadata.json") does not match requested format "KWin/Script"
Dec 12 18:11:39 solus wireplumber[1295]: wp-event-dispatcher: wp_event_dispatcher_unregister_hook: assertion 'already_registered_dispatcher == self' failed
Dec 12 18:11:39 solus wireplumber[1295]: wp-event-dispatcher: wp_event_dispatcher_unregister_hook: assertion 'already_registered_dispatcher == self' failed
Dec 12 18:11:39 solus wireplumber[1295]: wp-event-dispatcher: wp_event_dispatcher_unregister_hook: assertion 'already_registered_dispatcher == self' failed
Dec 12 18:11:39 solus wireplumber[1295]: wp-event-dispatcher: wp_event_dispatcher_unregister_hook: assertion 'already_registered_dispatcher == self' failed
Dec 12 18:11:39 solus wireplumber[1295]: spa.bluez5: BlueZ system service is not available
Dec 12 18:11:39 solus wireplumber[1295]: wp-device: SPA handle 'api.libcamera.enum.manager' could not be loaded; is it installed?
Dec 12 18:11:39 solus wireplumber[1295]: s-monitors-libcamera: PipeWire's libcamera SPA plugin is missing or broken. Some camera types may not be supported.
Dec 12 18:12:04 solus kwin_wayland[1231]: Failed to register with host portal QDBusError("org.freedesktop.DBus.Error.NoReply", "Did not receive a reply. Possible causes include: the remote application did not send a reply, the message bus security policy blocked the reply, the reply timeout expired, or the netw>
Dec 12 18:12:05 solus systemd[1178]: plasma-kcminit.service: start operation timed out. Terminating.
Dec 12 18:12:05 solus systemd[1178]: xdg-desktop-portal.service: start operation timed out. Terminating.
Dec 12 18:12:05 solus systemd[1178]: plasma-kcminit.service: Killing process 1314 (WaylandEventThr) with signal SIGKILL.
Dec 12 18:12:05 solus systemd[1178]: xdg-desktop-portal.service: Failed with result 'timeout'.
Dec 12 18:12:05 solus systemd[1178]: Failed to start xdg-desktop-portal.service - Portal service.
Dec 12 18:12:05 solus systemd[1178]: plasma-kcminit.service: Failed with result 'timeout'.
Dec 12 18:12:05 solus systemd[1178]: Failed to start plasma-kcminit.service - KDE Config Module Initialization.
Dec 12 18:12:05 solus systemd[1178]: Dependency failed for plasma-kcminit-phase1.service - KDE Configuration Module Initialization (Phase 1).
Dec 12 18:12:05 solus systemd[1178]: plasma-kcminit-phase1.service: Job plasma-kcminit-phase1.service/start failed with result 'dependency'.
Dec 12 18:12:05 solus systemd[1178]: Starting plasma-ksmserver.service - KDE Session Management Server...
Dec 12 18:12:05 solus systemd[1178]: Started plasma-kwallet-pam.service - Unlock kwallet from pam credentials.
Dec 12 18:12:05 solus systemd[1178]: Starting plasma-kded6.service - KDE Daemon 6...
Dec 12 18:12:05 solus systemd[1178]: Starting xdg-desktop-portal.service - Portal service...
Dec 12 18:12:05 solus /usr/lib64/xdg-desktop-portal/xdg-desktop-portal[1428]: Choosing gtk.portal for org.freedesktop.impl.portal.Lockdown as a last-resort fallback
Dec 12 18:12:15 solus systemd[1178]: plasma-ksplash.service: start operation timed out. Terminating.
Dec 12 18:12:15 solus systemd[1178]: plasma-ksplash.service: Main process exited, code=killed, status=15/TERM
Dec 12 18:12:15 solus systemd[1178]: plasma-ksplash.service: Failed with result 'timeout'.
Dec 12 18:12:15 solus systemd[1178]: Failed to start plasma-ksplash.service - Splash screen shown during boot.
Dec 12 18:12:34 solus plasma_waitforname[1226]: WaitForName: Service was not registered within timeout
Dec 12 18:12:34 solus systemd[1178]: dbus-:1.2-org.kde.KSplash@0.service: Main process exited, code=exited, status=1/FAILURE
Dec 12 18:12:34 solus systemd[1178]: dbus-:1.2-org.kde.KSplash@0.service: Failed with result 'exit-code'.
Dec 12 18:12:35 solus systemd[1178]: plasma-ksmserver.service: start operation timed out. Terminating.
Dec 12 18:12:35 solus systemd[1178]: xdg-desktop-portal.service: start operation timed out. Terminating.
Dec 12 18:12:35 solus systemd[1178]: plasma-kded6.service: start operation timed out. Terminating.
Dec 12 18:12:35 solus systemd[1178]: xdg-desktop-portal.service: Failed with result 'timeout'.
Dec 12 18:12:35 solus systemd[1178]: Failed to start xdg-desktop-portal.service - Portal service.
Dec 12 18:12:35 solus systemd[1178]: plasma-ksmserver.service: Failed with result 'timeout'.
Dec 12 18:12:35 solus systemd[1178]: Failed to start plasma-ksmserver.service - KDE Session Management Server.
Dec 12 18:12:35 solus systemd[1178]: Starting plasma-plasmashell.service - KDE Plasma Workspace...
Dec 12 18:12:35 solus systemd[1178]: plasma-kded6.service: Failed with result 'timeout'.
Dec 12 18:12:35 solus systemd[1178]: Failed to start plasma-kded6.service - KDE Daemon 6.
If there are any other logs or troubleshooting steps I should provide/try, let me know.