"cinnamon-settings network" crashes by attempt to configure Mobile Broadband

[Isolator70]

Mobile Broadband cannot be configured - Application crashes reproducible

It is not possible to configure Mobile Broadband Network connection

Steps to reproduce

Insert SIM card of German Provider "LIDL Connect" into SIM card slot of my Laptop (Fujitsu Lifebook E744, 4G/LTE capable modem).
PIN was entered and stored when prompted, Mobile Broadband was activated.
One can see some Mobile Network bars and the name "Lidl Connect" when looking at Cinnamon's Info area (where also the WiFi info is shown), so SIM and modem seems to work correctely:

Unfortunately up to this point there is no data flow via the SIM card (inserted in a mobile phone it works without problems).

Now goto Network ("Netzwerk") and try to check what can be done here.

Clicking the (empty) drop down list and selecting "Add a new connection ("Neue Verbindung hinzufügen") the window closes immediately.

If the Network Settings were opened by Terminal (cinnamon-settings network) one can see following output:

cinnamon-settings network
/usr/share/cinnamon/cinnamon-settings/cinnamon-settings.py:444: DeprecationWarning: Gtk.Window.set_wmclass is deprecated
self.window.set_wmclass(wm_class, wm_class)

** (cinnamon-settings.py:7386): CRITICAL **: 19:44:38.860: cc_shell_get_toplevel: assertion 'CC_IS_SHELL (shell)' failed

(cinnamon-settings.py:7386): Gtk-WARNING **: 19:44:38.864: Unknown type NMACountryInfo specified in treemodel country_store

(cinnamon-settings.py:7386): Gtk-WARNING **: 19:44:38.864: ../../../../gtk/gtktreestore.c:411: Invalid type (null)

(cinnamon-settings.py:7386): Gtk-WARNING **: 19:44:38.865: Unknown type NMAMobileAccessMethod specified in treemodel plan_store

(cinnamon-settings.py:7386): Gtk-WARNING **: 19:44:38.865: ../../../../gtk/gtktreestore.c:411: Invalid type (null)

(cinnamon-settings.py:7386): Gtk-WARNING **: 19:44:38.865: Unknown type NMAMobileProvider specified in treemodel providers_store

(cinnamon-settings.py:7386): Gtk-WARNING **: 19:44:38.865: ../../../../gtk/gtktreestore.c:411: Invalid type (null)
/usr/lib/python3/dist-packages/gi/overrides/Gio.py:42: Warning: ../../../gobject/gtype.c:4333: type id '0' is invalid
return Gio.Application.run(self, *args, **kwargs)
/usr/lib/python3/dist-packages/gi/overrides/Gio.py:42: Warning: can't peek value table for type '' which is not currently referenced
return Gio.Application.run(self, *args, **kwargs)
Speicherzugriffsfehler (Speicherabzug geschrieben)

Expected behaviour

By selecting the right Network ("Netzwerk") I can configure the connection to make it work.

Other information

My system:

inxi -Fz
System:
Kernel: 5.15.0-107-generic x86_64 bits: 64 Desktop: Cinnamon 6.0.4
Distro: Linux Mint 21.3 Virginia
Machine:
Type: Laptop System: FUJITSU product: LIFEBOOK E744 v: 10601583214
serial:
Mobo: FUJITSU model: FJNB270 v: L3 serial:
UEFI-[Legacy]: FUJITSU // Phoenix v: Version 1.27 date: 07/21/2020
Battery:
ID-1: CMB1 charge: 24.5 Wh (39.0%) condition: 62.9/72.4 Wh (86.9%)
volts: 10.9 min: 10.8
CPU:
Info: dual core model: Intel Core i5-4200M bits: 64 type: MT MCP cache:
L2: 512 KiB
Speed (MHz): avg: 1197 min/max: 800/3100 cores: 1: 1197 2: 1197 3: 1197
4: 1197
Graphics:
Device-1: Intel 4th Gen Core Processor Integrated Graphics driver: i915
v: kernel
Device-2: Chicony FJ Camera type: USB driver: uvcvideo
Display: x11 server: X.Org v: 1.21.1.4 driver: X: loaded: modesetting
unloaded: fbdev,vesa gpu: i915 resolution: 1600x90060Hz
OpenGL: renderer: Mesa Intel HD Graphics 4600 (HSW GT2)
v: 4.6 Mesa 23.2.1-1ubuntu3.122.04.2
Audio:
Device-1: Intel Xeon E3-1200 v3/4th Gen Core Processor HD Audio
driver: snd_hda_intel
Device-2: Intel 8 Series/C220 Series High Definition Audio
driver: snd_hda_intel
Sound Server-1: ALSA v: k5.15.0-107-generic running: yes
Sound Server-2: PulseAudio v: 15.99.1 running: yes
Sound Server-3: PipeWire v: 0.3.48 running: yes
Network:
Device-1: Intel Ethernet I217-V driver: e1000e
IF: enp0s25 state: down mac:
Device-2: Intel Wireless 7260 driver: iwlwifi
IF: wlp2s0 state: up mac:
IF-ID-1: wwan0 state: down mac:
Bluetooth:
Device-1: Intel Bluetooth wireless interface type: USB driver: btusb
Report: hciconfig ID: hci0 state: up address: bt-v: 2.1
Drives:
Local Storage: total: 447.13 GiB used: 228.52 GiB (51.1%)
ID-1: /dev/sda vendor: Intenso model: SATA III SSD size: 447.13 GiB
Partition:
ID-1: / size: 290.92 GiB used: 228.52 GiB (78.6%) fs: ext4 dev: /dev/sda5
Swap:
ID-1: swap-1 type: file size: 15.62 GiB used: 0 KiB (0.0%) file: /swapfile
Sensors:
System Temperatures: cpu: 52.0 C mobo: N/A
Fan Speeds (RPM): N/A
Info:
Processes: 257 Uptime: 53m Memory: 7.65 GiB used: 3.11 GiB (40.6%)
Shell: Bash inxi: 3.3.13