We’ve released a small but mighty feature to the Pull from FTP step!
The new “Archive file once processed” setting allows this step to cycle through a list of files in a folder, moving them after each one has been processed into a different folder.
Using this setting, you can build Flows that check folders for new files and process them one by one until the folder is empty.
Source: https://parabola.io/updates/process-entire-folders-of-files-using-ftp