AWS S3 sync method- possible to ignore modified files completely?
Would aws s3 sync --size-only work for you?

--size-only (boolean) Makes the size of each key the only criteria used to decide whether to sync from source to destination.

(Emphasis mine.)
I'm purposefully modifying every locally synced files (although directory name is unique and unmodified), which makes the sync method try to redownload the whole bucket, taking an excess of time.
Copying the local files (to preserve their timestamp + size) isn't really an option since the bucket size is so big, and AWS sync docs don't seem to have an option to exclude modified files.
I was hoping there's a way to prevent attempting to redownload a directory if it exists locally.
Any ideas?
Thanks a lot