At the moment, many nutrition tracking apps can import data from Garmin Connect, but only MyFitnessPal can import consumption data back into Garmin Connect. I'd like to request that Garmin allow other apps to provide consumption data to Garmin Connect, because otherwise the data I enter into the other app will never sync back to my watch! I've gotten increasingly disappointing in MFP and their development trajectory lately, as the app has gotten more cluttered and harder to use, and they have not made any improvements to the core nutrition tracking part of the app in years.
I realize this is more of a community forum, but I can no longer find the "Give Feedback" option in the connect app, and it seems to have become harder to find a way to email the Garmin team directly. Also, I have already emailed the developer of the app(s) that I've used to request, and they've mostly said it requires support from Garmin to accomplish (the part about sending data back to Connect), so I don't think it's totally on 3rd party developers to enable this capability. So I hope that Garmin will allow users of other apps besides MFP to enable two-way sync.