Support for Drupal 7 is ending on 5 January 2025—it’s time to migrate to Drupal 10! Learn about the many benefits of Drupal 10 and find migration tools in our resource center.
Drupal uses managed file widget (managed_file form #type) in most of the user interfaces, fbsmp uses file widget instead.
At my site a lot of users that don't see the upload button report this as an issue.