Sorry to hear you are having issues.
Not all Windows sounds are changed with a sound pack
With SP app opened viewing that sound pack click on edit sound pack
and you can scroll though the sounds that were changed for that pack .
While there you can make changes to that pack add or remove some sounds .
There are some Windows sounds that can't be changed , I don't have a list of those ,
that changes from time to time as with Windows updates .
Stardock Community Assistant