I was not able to sync Renpho weight to Garmin Connect App using the old posts. However, I found a straight forward, simple and elegant way. It imports Weight, BMI and Body Fat.
1. On the phone ->Open Renpho App -> Settings -> Turn ON Fitbit and choose All
2. On the browser (I used a computer) open Fitbit site and log in (before Garmin I owned a Fitbit and my account is still active) - or open an account - no need to own a watch.
Go to Settins -> Data export and choose weight only. The feature allows downloading the current month data in CVS format.
Now, the beauty of this method: open the CVS file and delete all unnecessary data. First time I kept just one day readings.
3. On the browser (I used a computer) open Garmin Connect site and log in. Hit the Upload or Import Activity icon and drag the CVS file to the Drag and Drop window.
You can verify your Weight, BMI and Body Fat data in the Daily Summary tab under Weight tab, or on the phone after syncing.