I installed it from Windows Store, opened a blank text document, and the styles box appears to contain white text on a white background.
I opened a blank spreadsheet, typed in something, tried to create a pivot table, and it only expanded the selection without showing the dialog box.
I restarted it and those bugs were fixed, but the Pivot Table UI is still the ugly non-interactive one found in LibreOffice (which Excel got rid of 26+ years ago).
Uninstalled.