Comment by DebtDeflation

Are you sure about that? I have a Garmin Fenix 6 and the Connect app on Android. While it's true that all data is stored locally on the watch and it doesn't need to be tethered to a phone to work, I'm pretty sure that syncing the watch to the Connect app does require the Connect app to be connected to the server. I have experienced this multiple times, after completing a hike in a remote area and I try to sync the Hike Activity to Connect it fails due to not having a cellular connection despite the watch being connected to the phone via Bluetooth.