Sorry to hear you are having trouble.
If Windows Blinds has a new skin I like (eg a free one) I download it. But when I double click the WBA file (in File Explorer) nothing happens.
If you were able to DL the skin, there is nothing here that would stop you from applying it - no 'limit'.
If you do this, and nav to the .wba location, does that work?
Stardock Support Manager