Most canyoneers use digital maps on their phone as their primary map. These maps almost always need to be downloaded before the canyoneering trip starts because there is often little or no cell phone reception on canyoneering routes. It's a good idea to have both topographic maps and satellite imagery downloaded to your device.
A paper map can be helpful, especially for longer multi-day canyons when a cell phone battery may not last the whole trip.
If you can make sure you drop into the correct canyon, you're pretty much guaranteed success. Most accidents and rescues that involve navigation errors are from groups dropping into the wrong canyon.