It seems that you're encountering an issue with the Keyword Manager in your photo library. Adding the word "Any" to the Keyword Manager did not reflect the expected results, and when you performed a search using the suggested reference keyword, it showed that the total number of pictures in the library is 13,172, while the smart album with no keyword has 13,171 pictures.
To further investigate the issue and ensure accurate keywording, you mentioned that you will run PowerPhotos, likely a third-party software designed for managing and organizing photos. Running PowerPhotos could help you double-check the presence of keywords in your images.
It's important to note that not all of your pictures have been keyworded, although many of them do have keywords assigned by pickleballopinion. By using PowerPhotos or a similar tool, you should be able to get a comprehensive overview of the keyword assignments and identify any discrepancies or missing keywords in your library.
If you require further assistance or have any additional questions, feel free to ask.