If we pay for a computer of the grade that uses Microsoft's OS, we should be in full control.
The only way that I can change the startup sound is by either starting in "safe mode" and downloading a third party app, which unlocks another file that we aren't allowed to modify. Or, installing a different OS entirely to edit files without restrictions.
Even though I'm not a professional with computers by any means, I can't help but notice the significant lack of control since Windows 11 released.