I have read that as of October 2019, Dropbox no longer supports connection to the Samsung "My Files" app. I suggest that Dropbox reconsiders this decision, because:
1. Other big companies' cloud storage services such as OneDrive and Google Disk are allowing connection to the Samsung "My Files" app.
2. Dropbox already allows connection to the iOS "Files" app.
3. This encourages Samsung users to easily use Dropbox within one files app, which could convert them into paid users.
4. This will not take away from the usage of the Dropbox app, since many great features are still needed to be used on the Dropbox app itself. The Samsung "My Files" app just helps to easily reach the stored files of many cloud storage services in one place, and nothing more after that.
Thank you Dropbox team for all your wonderful efforts for us.