I have recently made a number of albums from within the OneDrive photos desktop app, but I am unable to see them anywhere other than the onedrive "photos" tab, attach them to an email or view them from within the onedrive "pictures" files directory.
I therefore have a number of folders in the onedrive: pictures folders, but also a number in the onedrive: photos: album that do not show in either section - why is that?
Albums are not file system features (ie they are not folders) . Adding images to an album does not change the folder they are stored in. An album is a view into your collection. While folders are rigid structures, albums (and search hashtags) enable you to organise your images in other ways.
There are a bunch of explanatory articles on the web if you want more . Google "onedrive albums vs folders" for example.