This place is dead but here goes.
I'm not sure it exactly answers your question the way you want BUT it is possible to create a playlist using local files with a sensible name (album name, artist/album name etc) in order, tracknames and if you own or have local copies of the file "it just works" in ol' Todd Howard style.
If the playlist is listed as public then others can find it in their search results and if the metadata on their local files match they can like/follow/add it and it'll work for them.
I only found this out because I create artist discography/album playlists for things not on spotify and found that my privacy settings had them as public only to discover they had likes even when every song on the list was local.
May not exactly be the answer you're looking for.
You seem to want the content uploaded to spotify's servers maybe? idk, but tldr; ayyyy you get the files, add 'em create a public playlist without a stupid name with good album art and when you search it, when others search it, they get a match if they use local files. Just don't be a zoomer k