Transfering routes & tracks from iPhone to GPSMAP 66i

Is there a way to transfer routes and tracks for third party iPhone apps to the 66i? Garmin Explore does not show up as a "share" option from other apps such as Gaia, Maps 3D, Footpath etc.

While Garmin Connect does show up as "share" option on other apps, the 66i is not supported by Garmin Connect for the purpose of transferring courses. And even if it did, Garmin Connect requires Internet connection.

Being able to transfer routes/tracks designed on other apps is essential as Garmin devices suck big time for planning purposes due to how maps are rendered and specially to how slow zooming and panning are.