This is really about Dropbox’s web display of text files. It does not “soft wrap” like most editors to make the lines fit the width of the display.
In reality, you do not want line breaks added, but just want it displayed more nicely.
You can get this to display better in Dropbox if you export as a different file type. For example, Dropbox will wrap text when displaying Markdown file types. If you change your “Save to Dropbox” action to save the file with a
.md file instead of
.txt, it will come out better for on-screen viewing in their web interface.
You can do that by editing the action, and changing the “Name” value in the Dropbox action step to end in