Ok,
I removed all my taskbar tweaks (Free launchbar, Explorer Patcher and Openshell) from my computer.
Now my Windows 11 desktop + taskbar looks like this (it is in French, but I do not want to change it).
We are talking about the blue icon at below left which is the Windiows start button. ... Ok !
Then I installed Open Shell. There is now another start button, which is called "Menu Démarrer" in my case (may be it's the bluish shell icon when you install, ... I don't know but you can chose it). When you click at the new start button, you will have someting like this:
Look at the two terms I put in yellow. If your computer is in English, the line "Paramètres" will say "Settings", but "Open Shell Menu" will be the same.
Now click on "Open Shell Menu", also in yellow.
A new window will open, see next picture.
Important: Click on "Show
all settings" above ! There will then be more menus shown. If not, close "Open Shell" and reopen it.
Now you will see this:
Click on "Main menu" (yellow) and then tick "Show Start Screen shortcut" (also yellow).
Then click ok (below right) in "Open Shell" and close it.
Then re-open it. You will see a new entry in your "Open Shell start menu" (the first one in my picture below, called "Menu Démarreur (Windows)" on my computer which should read "Windows start menu" on your computer.
Now click on this new entry (let your left finger on the mouse button without releasing it) and draw the entry to your destop. Then release. Now you have the "Windows Start menu" shortcut on your desktop.
Then click on the shortcut icon with the right mouse button. The rightclick = context menu will open. Find the entry "Pin to taskbar" and
leftclick on it.
Now the "Windows start men" should be on your taskbar.
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Just try whether it works.
If you want another icon on the shortcut (you want the original blue windows icon back), please come back here. I'll explain how to do that.
But I'd like to first verify with you, whether it works at all.
Regards