Login in Plasma Wayland is very slow

It happened some time ago, but I have had a working KDE Plasma Wayland for a long time, so there is something wrong in the latest updates.
My system is a Debian/Sid on a Microsoft Surface Pro 9 with a patched kernel from linux-surface project.

The problem is logging in Plasma Wayland (no problem in X11) because the desktop session appears after a time comprised between 30 seconds and 2 minutes.

systemd-analyze --user blame | head -5
1min 30.011s plasma-ksmserver.service
33.495s plasma-kded6.service
33.482s plasma-plasmashell.service
542ms xdg-desktop-portal.service
322ms evolution-source-registry.service

sudo journalctl -p 3 -xb
sudo journalctl -p 3 -xb
Jan 20 23:06:13 Surfix9 systemd-udevd[383]: /etc/udev/rules.d/99-i2c.rules:1 Failed to resolve group ‘i2c’, ignoring: Not a system group
Jan 20 23:06:13 Surfix9 kernel: Error: Driver ‘pcspkr’ is already registered, aborting…
Jan 20 23:06:15 Surfix9 (udev-worker)[414]: input31: /etc/udev/rules.d/99-disable-ipts-touch.rules:1 ATTR{enabled}=“0”: Could not chase sysfs attribute “/sys/devices/virtual/input/input31/enabled”, ignoring: File o directory non esistente
Jan 20 23:06:15 Surfix9 (udev-worker)[414]: mouse4: /etc/udev/rules.d/99-disable-ipts-touch.rules:1 ATTR{enabled}=“0”: Could not chase sysfs attribute “/sys/devices/virtual/input/input31/mouse4/enabled”, ignoring: File o directory non esistente
Jan 20 23:06:15 Surfix9 (udev-worker)[422]: event26: /etc/udev/rules.d/99-disable-ipts-touch.rules:1 ATTR{enabled}=“0”: Could not chase sysfs attribute “/sys/devices/virtual/input/input31/event26/enabled”, ignoring: File o directory non esistente
Jan 20 23:06:23 Surfix9 sddm-helper[1403]: gkr-pam: unable to locate daemon control file
Jan 20 23:07:57 Surfix9 systemd[1409]: Failed to start plasma-kded6.service - KDE Daemon 6.
░░ Subject: A start job for unit UNIT has failed
░░ Defined-By: systemd
░░ Support: Debian -- User Support
░░
░░ A start job for unit UNIT has finished with a failure.
░░
░░ The job identifier is 122 and the job result is failed.
Jan 20 23:07:57 Surfix9 systemd[1409]: Failed to start xdg-desktop-portal.service - Portal service.
░░ Subject: A start job for unit UNIT has failed
░░ Defined-By: systemd
░░ Support: Debian -- User Support
░░
░░ A start job for unit UNIT has finished with a failure.
░░
░░ The job identifier is 186 and the job result is failed.
Jan 20 23:07:57 Surfix9 systemd[1409]: Failed to start plasma-ksmserver.service - KDE Session Management Server.
░░ Subject: A start job for unit UNIT has failed
░░ Defined-By: systemd
░░ Support: Debian -- User Support
░░
░░ A start job for unit UNIT has finished with a failure.
░░
░░ The job identifier is 125 and the job result is failed.
Jan 20 23:08:25 Surfix9 org_kde_powerdevil[1769]: [ 1769] Error(s) opening ddc devices
Jan 20 23:08:25 Surfix9 org_kde_powerdevil[1769]: [ 1769] Error EACCES(-13): Permesso negato opening /dev/i2c-4
Jan 20 23:08:25 Surfix9 org_kde_powerdevil[1769]: [ 1769] Error EACCES(-13): Permesso negato opening /dev/i2c-5
Jan 20 23:08:25 Surfix9 org_kde_powerdevil[1769]: [ 1769] Error EACCES(-13): Permesso negato opening /dev/i2c-6
Jan 20 23:08:25 Surfix9 org_kde_powerdevil[1769]: [ 1769] Error EACCES(-13): Permesso negato opening /dev/i2c-7
Jan 20 23:08:25 Surfix9 org_kde_powerdevil[1769]: [ 1769] Error EACCES(-13): Permesso negato opening /dev/i2c-8
Jan 20 23:08:25 Surfix9 org_kde_powerdevil[1769]: [ 1769] Error EACCES(-13): Permesso negato opening /dev/i2c-9
Jan 20 23:08:25 Surfix9 org_kde_powerdevil[1769]: [ 1769] Error EACCES(-13): Permesso negato opening /dev/i2c-10
Jan 20 23:08:25 Surfix9 org_kde_powerdevil[1769]: [ 1769] Error EACCES(-13): Permesso negato opening /dev/i2c-11
Jan 20 23:08:25 Surfix9 org_kde_powerdevil[1769]: [ 1769] Error EACCES(-13): Permesso negato opening /dev/i2c-12
Jan 20 23:08:25 Surfix9 org_kde_powerdevil[1769]: [ 1769] Error EACCES(-13): Permesso negato opening /dev/i2c-13
Jan 20 23:08:25 Surfix9 org_kde_powerdevil[1769]: [ 1769] Error EACCES(-13): Permesso negato opening /dev/i2c-14
Jan 20 23:08:25 Surfix9 org_kde_powerdevil[1769]: [ 1769] Error EACCES(-13): Permesso negato opening /dev/i2c-15
Jan 20 23:08:25 Surfix9 org_kde_powerdevil[1769]: [ 1769] Error EACCES(-13): Permesso negato opening /dev/i2c-16
Jan 20 23:13:02 Surfix9 NetworkManager[934]: [1768947182.1684] device (wlp0s20f3): Couldn’t initialize supplicant interface: Name owner lost
Jan 20 23:24:54 Surfix9 systemd-coredump[10208]: Process 10183 (kwalletd6) of user 1001 dumped core.

                                             Module libuuid.so.1 from deb util-linux-2.41.3-3.amd64
                                             Module libgomp.so.1 from deb gcc-15-15.2.0-12.amd64
                                             Module libsystemd.so.0 from deb systemd-259-1.amd64
                                             Module libblkid.so.1 from deb util-linux-2.41.3-3.amd64
                                             Module libzstd.so.1 from deb libzstd-1.5.7+dfsg-3+b1.amd64
                                             Module libudev.so.1 from deb systemd-259-1.amd64
                                             Module libatomic.so.1 from deb gcc-15-15.2.0-12.amd64
                                             Module libmount.so.1 from deb util-linux-2.41.3-3.amd64
                                             Module libgcc_s.so.1 from deb gcc-15-15.2.0-12.amd64
                                             Module libstdc++.so.6 from deb gcc-15-15.2.0-12.amd64
                                             Stack trace of thread 10183:
                                             #0  0x000075cca8ca13dc __pthread_kill_implementation (libc.so.6 + 0x973dc)
                                             #1  0x000075cca8c4a942 __GI_raise (libc.so.6 + 0x40942)
                                             #2  0x000075cca8c324ac __GI_abort (libc.so.6 + 0x284ac)
                                             #3  0x000075cca92dc53b n/a (libQt6Core.so.6 + 0xdc53b)
                                             #4  0x000075cca92dd34f _ZNK14QMessageLogger5fatalEPKcz (libQt6Core.so.6 + 0xdd34f)
                                             #5  0x000075cca8351146 n/a (libQt6Gui.so.6 + 0x151146)
                                             #6  0x000075cca83ed728 _ZN22QGuiApplicationPrivate21createEventDispatcherEv (libQt6Gui.so.6 + 0x1ed728)
                                             #7  0x000075cca93a915f _ZN23QCoreApplicationPrivate4initEv (libQt6Core.so.6 + 0x1a915f)
                                             #8  0x000075cca83ed7ce _ZN22QGuiApplicationPrivate4initEv (libQt6Gui.so.6 + 0x1ed7ce)
                                             #9  0x000075cca9db2b4d _ZN19QApplicationPrivate4initEv (libQt6Widgets.so.6 + 0x1b2b4d)
                                             #10 0x00005da8c8b248f6 n/a (/usr/bin/kwalletd6 + 0xb8f6)
                                             #11 0x000075cca8c33f75 __libc_start_call_main (libc.so.6 + 0x29f75)
                                             #12 0x000075cca8c34027 __libc_start_main_impl (libc.so.6 + 0x2a027)
                                             #13 0x00005da8c8b24f01 n/a (/usr/bin/kwalletd6 + 0xbf01)
                                             
                                             Stack trace of thread 10190:
                                             #0  0x000075cca8ca76de __syscall_cancel_arch (libc.so.6 + 0x9d6de)
                                             #1  0x000075cca8c9be84 __internal_syscall_cancel (libc.so.6 + 0x91e84)
                                             #2  0x000075cca8c9becd __syscall_cancel (libc.so.6 + 0x91ecd)
                                             #3  0x000075cca8d112ce __GI_ppoll (libc.so.6 + 0x1072ce)
                                             #4  0x000075ccaa4a6af4 n/a (libglib-2.0.so.0 + 0x5faf4)
                                             #5  0x000075ccaa4a71d0 g_main_context_iteration (libglib-2.0.so.0 + 0x601d0)
                                             #6  0x000075cca9604dc8 _ZN20QEventDispatcherGlib13processEventsE6QFlagsIN10QEventLoop17ProcessEventsFlagEE (libQt6Core.so.6 + 0x404dc8)
                                             #7  0x000075cca93afe53 _ZN10QEventLoop4execE6QFlagsINS_17ProcessEventsFlagEE (libQt6Core.so.6 + 0x1afe53)
                                             #8  0x000075cca949896f _ZN7QThread4execEv (libQt6Core.so.6 + 0x29896f)
                                             #9  0x000075cca9a0631e n/a (libQt6DBus.so.6 + 0x3f31e)
                                             #10 0x000075cca951c6e4 n/a (libQt6Core.so.6 + 0x31c6e4)
                                             #11 0x000075cca8c9f489 start_thread (libc.so.6 + 0x95489)
                                             #12 0x000075cca8d1dd38 __clone3 (libc.so.6 + 0x113d38)
                                             ELF object binary architecture: AMD x86-64

░░ Subject: Process 10183 (kwalletd6) dumped core
░░ Defined-By: systemd
░░ Support: Debian -- User Support
░░ Documentation: man:core(5)
[…]

kwalletd6 crashes many times, but I can’t put more than this amount of text in this post. Can you help me solving this problem?