New Teams cannot be set to start automatically

After identifying that I didn't had the setting visible I started to think that there were some problem with Windows rather than New Teams. I searched and found this article:
https://answers.microsoft.com/en-us/windows/forum/all/startup-app-in-menu-settings-is-missing-in-windows/d4ec7fe9-3f28-4b84-8757-9ecf6179d53a?page=2

The issue actually matched my machine. I also had a missing Startup App setting in the Settings App. I opened the registry I found that I were missing some of the mentioned keys.
First I added SupportUwpStartupTasks REG_DWORD 0x1. That solved the missing setting in the Settings app.
I opened the Startup App meny in the settings and I saw that New Teams were still grayed out. That wasn't the complete solution to the problem.
Second, I added SupportFullTrustStartupTasks REG_DWORD 0x1.
After I added this second registry key everything started to work as expected.

Also there are two additional keys that should be set:
EnableFullTrustStartupTasks REG_DWORD 0x2
EnableUwpStartupTasks REG_DWORD 0x2

Now I need to find out why these two keys were missing on my machine. My suspicion is that they were lost during upgrade from Windows 10 to WIndows 11, but we'll see about that.

Thanks for pushing me in the right direction so that I finally could find the solution.