I think I need to have a certain garage door opener that is connected to a smart home system. It would be nice if I can program the watch to pickup my remote code.
I use the ConnectIQ IOT widget and send HTML call to my Vera home control system that is linked to my Chamberlain Garage controller.
As this requires you to be connected to the phone and also that the phone be on my home network, I use a VPN to ensure it is connected whether or not I am on the WiFi with my phone.
I think I need to have a certain garage door opener that is connected to a smart home system.
Generally true, yes. Then you would need a connectIQ app/widget on the fenix that would talk to a BT paired phone to do a web request out to your smart home system.
It would be nice if I can program the watch to pickup my remote code.
If you mean that you want your fenix to use garage door opener compatible RF commands to open the door like a usual "HomeLink" or "visor remote", that's not possible given the wireless communication capability of the Garmin.