The best GPS for touring is a phone.
The more crap you add, the more crap you have to worry about charging. You already have a phone. Keep it simple and use what you already have. Leave the gadgets at home.
Not grasping the logic here (no need to explain it).
Option 1):
> use the phone for navigation,
> it pulls lots of power to do so,
> phone may well be low or out of power when/if needed as a safety device or to call for help(injury, significant mech breakdown, weather forecast/tracking, crime..)
> best to carry a backup battery bank(a heavy, extra "gadget")
> need to carry a charger and USB cord that charges both devices
Option 2):
> reserve phone as nav backup,
> phone set to airplane mode or turned off when not needed, phone battery in good shape when/if emergency arrives, severe weather tracking, simple text communication
> use cycling(or hiking) gps for navigation that's designed for use with long battery life
> skip carrying a heavier battery bank
> carry a usb charger and cord that charges both phone and cycling gps
Same number of items carried in both instances. Second option is lighter in weight and with better tools for the jobs at hand.
I choose door number two.
You do you..doesn't matter to me.