I think that you can get course following to work with Bluetooth? The phone can just send a notification when it approaches the fork.
Though if you want to use your watch as a primary navigation device, you likely need to use LCD/OLED. eInk is not great for interactive map use, not a great use-case for Pebble.
For backup, I like carrying a Garmin satellite communicator. It has its own offline maps and a way to call for rescue in a pinch.
This is the main value of the watch to me. I like it as a standalone tool in the wilderness. I am not in the market for a phone peripheral. To me, the phone app is a peripheral to setup/maintain the watch and manage its data. But during hikes they are not connected at all.
I also really like the "course following" navigation on the watch and the customizable data pages. So I can have at my wrist a concise dashboard of timing, distance, elevation, ascent/descent, and upcoming turn guidance as I approach trail junctions. It's there at a glance.
I do also have mapping software on the phone for redundancy and other purposes, but the watch will get me to my destination on its own.