Welcome window outside of the screen

I just updated MuseScore to the latest version (4.0-1). Now, whenever I start the application I just see a greyed-out window of the standard writing interface, with no score opened. Running it from the console, I get the following output:

QEventLoop: Cannot be used without QApplication
QEventLoop: Cannot be used without QApplication
Gtk-Message: 09:49:36.183: Failed to load module "appmenu-gtk-module"
09:49:36.188 | INFO  | main_thread | GlobalModule | onPreInit: log path: /home/l0drex/.local/share/MuseScore/MuseScore4/logs/MuseScore_221216_094936.log
09:49:36.188 | INFO  | main_thread | GlobalModule | onPreInit: === Started MuseScore 4.0.0, build number  ===
09:49:36.204 | WARN  | main_thread | DiagnosticsModule | onInit: crash handling disabled
09:49:36.209 | DEBUG | main_thread | ShortcutsRegister | expandStandardKeys: removed 5 shortcut, because they are not bound to standard key
09:49:36.209 | DEBUG | main_thread | ShortcutsRegister | expandStandardKeys: added 3 shortcut, because they are alternative shortcuts for the given standard keys
09:49:36.209 | WARN  | main_thread | Qt         | QIODevice::read (QFile, "/home/l0drex/.local/share/MuseScore/MuseScore4/shortcuts.xml"): device not open
09:49:36.209 | WARN  | main_thread | Qt         | QIODevice::read (QFile, "/home/l0drex/.local/share/MuseScore/MuseScore4/midi_mappings.xml"): device not open
09:49:36.414 | DEBUG | main_thread | LinuxAudioDriver | open: Connected to default
09:49:36.414 | ERROR | main_thread | MuseSamplerLibHandler | MuseSamplerLibHandler: Unable to open MuseSampler library, path: libMuseSamplerCoreLib.so
09:49:36.414 | ERROR | main_thread | MuseSamplerResolver | checkLibrary: Incompatible MuseSampler library; ignoring
09:49:36.495 | DEBUG | main_thread | InstrumentTemplate | read: InstrumentTemplate:: init instrument  not found
09:49:36.497 | DEBUG | main_thread | AlsaMidiInPort | connect: Connected to -1
09:49:36.497 | DEBUG | main_thread | AlsaMidiOutPort | connect: Connected to -1
09:49:36.510 | DEBUG | main_thread | Score      | tick2segment: no measure for tick -1
09:49:36.526 | DEBUG | main_thread | Score      | tick2segment: no measure for tick -1
09:49:36.529 | ERROR | main_thread | PluginsConfiguration | updatePluginsConfiguration: [401] Die Datei existiert nicht
09:49:36.529 | WARN  | main_thread | CloudService | readTokens: Could not find the tokens file: /home/l0drex/.local/share/MuseScore/MuseScore4/cred.dat
09:49:36.529 | WARN  | main_thread | IpcSocket  | connect: failed connect to server
09:49:36.529 | WARN  | main_thread | IpcSocket  | connect: failed connect to server
09:49:36.529 | INFO  | main_thread | IpcSocket  | connect: success connected to ipc server
09:49:36.529 | DEBUG | main_thread | WorkspacesDataProvider | rawData: get data from default workspace, key: ui_settings
09:49:36.529 | DEBUG | main_thread | WorkspacesDataProvider | rawData: get data from default workspace, key: ui_states
09:49:36.529 | DEBUG | main_thread | WorkspacesDataProvider | rawData: get data from default workspace, key: ui_toolconfigs
09:49:36.529 | INFO  | 140467970762432 | IpcServer  | listen: id: "fe15a2b61eb745adb69cadfb3d854000" 
09:49:36.529 | DEBUG | main_thread | UiActionsRegister | updateEnabledAll: currentCtx: UiCtxUnknown
09:49:36.532 | DEBUG | main_thread | Score      | tick2segment: no measure for tick -1
09:49:36.538 | DEBUG | main_thread | Score      | tick2segment: no measure for tick -1
09:49:36.539 | DEBUG | main_thread | WorkspacesDataProvider | rawData: get data from default workspace, key: palettes
09:49:36.539 | DEBUG | main_thread | PaletteWorkspaceSetup | setup: no palette data in workspace, will use default
09:49:36.542 | DEBUG | main_thread | Score      | tick2segment: no measure for tick -1
09:49:36.548 | DEBUG | main_thread | Score      | tick2segment: no measure for tick -1
09:49:36.820 | DEBUG | main_thread | UiActionsRegister | updateEnabledAll: currentCtx: UiCtxUnknown
09:49:36.997 | ERROR | main_thread | AppShellConfiguration | sessionProjectsPaths: [401] Die Datei existiert nicht
09:49:36.997 | DEBUG | main_thread | Qt         | onFireOpen: try open uri: musescore://home, page: {"modal":"","params":{"sync":true},"path":"","sync":true,"type":1,"uri":"musescore://home"}
09:49:37.534 | DEBUG | main_thread | UiActionsRegister | updateEnabledAll: currentCtx: UiCtxHomeOpened
09:49:37.535 | DEBUG | main_thread | Qt         | onFireOpen: try open uri: musescore://firstLaunchSetup, page: {"modal":"","params":{"sync":true},"path":"FirstLaunchSetup/FirstLaunchSetupDialog.qml","sync":true,"type":2,"uri":"musescore://firstLaunchSetup"}
09:49:37.549 | DEBUG | main_thread | Qt         | onFireOpen: try open uri: musescore://notation, page: {"modal":"","params":{"sync":true},"path":"","sync":true,"type":1,"uri":"musescore://notation"}
09:49:37.550 | DEBUG | main_thread | WorkspacesDataProvider | setRawData: set data to default workspace, key: ui_states
09:49:37.614 | DEBUG | main_thread | UiActionsRegister | updateEnabledAll: currentCtx: UiCtxUnknown
09:49:37.616 | WARN  | main_thread | Qt         | QObject::connect(QQuickItem, mu::uicomponents::PopupViewCloseController): invalid nullptr parameter
09:49:37.616 | WARN  | main_thread | Qt         | QObject::connect(QObject, mu::uicomponents::PopupViewCloseController): invalid nullptr parameter
09:49:37.616 | DEBUG | main_thread | UiActionsRegister | updateEnabledAll: currentCtx: UiCtxUnknown
09:49:37.616 | DEBUG | main_thread | UiActionsRegister | updateEnabledAll: currentCtx: UiCtxUnknown
09:49:37.991 | DEBUG | 140467535992512 | Score      | tick2segment: no measure for tick -1
09:49:38.678 | ERROR | 140467228370624 | UpdateService | parseRelease: failed parse, err: "Ungültiger Wert" 
09:49:38.678 | ERROR | main_thread | UpdateScenario | doCheckForUpdate: Unable to check for update, error: [1701] 

I am unable to close the application and have to stop it from the system manager (or cancel it from the terminal).

I see that a popup window is opened, but it's somehow outside of my monitor, so I can't access it. I only noticed it from the application overview and the screenshot utility.

I guess that could be a bug from KDE and their window manager, since I also have an unusual screen setup (see the attached screenshot). But then again there are these error messages in the console…

Detailed system specs:

Operating System: Arch Linux
KDE Plasma Version: 5.26.4
KDE Frameworks Version: 5.101.0
Qt Version: 5.15.7
Kernel Version: 6.0.12-zen1-1-zen (64-bit)
Graphics Platform: X11
Processors: 12 × Intel® Core™ i5-10400F CPU @ 2.90GHz
Memory: 15.5 GiB of RAM
Graphics Processor: NVIDIA GeForce GTX 1060 6GB/PCIe/SSE2
Product Name: H570 Phantom Gaming 4