CPU 100%, Fan running crazy, task manager freezes since updating to Windows 11

Hi (thanks for your time and help),

my Inspiron 15 2-in-1 (7506) does crazy things since upgrading to Windows 11 (it has done this about a year ago already with Windows 10, then Dell sent about 4 BIOS-updates every some weeks that cured it).

The CPU is always at 100% (says the task manager when I open it, but there's no program showing in the left cpu-column that's causing this). The PC is running fine if you don't open the task manager. All other programs are running without lags, no fan turning, when task manager is closed. When you're doing some office stuff and little browsing, after some minutes the fan starts turning like crazy. If you want to provoke the fan turning crazy, you can turn on the task manager. The task manager freezes immediately (just the task manager, you can switch without problems to other programs that are all running normal), fan going crazy. You can't switch buttons in the task manager anymore (look at the screenshot I uploaded), you can't close it anymore. The only thing possible is to click on the settings-button. But if you change some setting and want to close it, the task manager freezes again and doesn't save the settings.

My windows 11 energy setting was set to "balanced". Now I changed it to "highest power". Task manager problem is the same, but the fan-starting-turning-like-crazy-after-some-office-and-browsing-time is totally gone!

Perhaps, you can help me. Thanks!

Greetings from Germany.

- edit: picture cut to relevant size -

-2nd edit: many people seem to have this problem:

https://answers.microsoft.com/en-us/windows/forum/all/task-manager-not-working-in-windows-11/dc1e0bd4-d11d-4fa9-b04a-705ef2334f12?page=1

https://answers.microsoft.com/en-us/windows/forum/all/task-manager-issues-windows-11/ad4dec7e-9ae5-4704-b203-e0722d7deda2

A recommendation is to update Intel display drivers via Windows update -> optional updates. I'll try this.