Your phone’s GPS signal will work fine with any mapping app. Even without a cell tower signal. Just make sure you download/cache the maps of where you’ll be before you head out…you need cell service, or an internet connection to do that.
Even Google Maps in topo view works reasonably well. Again, just have to cache the maps ahead of time.
But to answer your question. Yes, a handheld GPS will work too. But it’s basically the same thing as your phone and an app. Just with all the maps already loaded into it.