sure, i understand that is not the case, as that link was about rclone mount.
just pointing out that rclone can/does have issue with empty directories.
and perhaps other tools as well.
the most i have used/tested is 1,000,000 objects using wasabi, a s3 clone know for hot storage,
in my testing and based on forum posts, nothing is faster.
this post might be of use.
https://forum.rclone.org/t/fastest-way-to-check-for-changes-in-2-5-million-files/25957/11