I uninstalled everything and reinstalled it 3 times, but the problem persists. What’s next?
I assume that you are still on Windows 10 Pro?
Did LibreOffice install OK and could it be run from the Start menu? If it can run then it is just a matter of right-clicking on the shortcut in the Start menu, selecting More > Pin to Taskbar then dragging shortcut from taskbar to desktop. However, I suspect there is more to your question…
If that’s the only issue: Create the shortcut manually.