Open Cycling Maps combines OSM data with open source topo data and works really well. The gold standard for digital hiker is a gpx track made by experienced mountaineer, on top of OCM.

Between that, satellite imagery and offline capabilities of a modern phone and a hiking app that supports these formats you're all set.

The reason that you should have a topo map and compass, and know how to use them is that your battery cannot be expected to serve you throughout a multi-day hiking/camping trip.