Don't forget that Finder has customisable tags which sync perfectly across iCloud. They are a top-level browsing option on the iOS Files app. Probably you were thinking of something more tag-first but it does exist. :)

Personally I really like the file/folder model because I can sync the whole caboodle to my hard drive, copy it to a USB backup, possibly transfer it to another operating system, knowing that I've captured the whole story.