I highly suggest checking out Natural Atlas (https://naturalatlas.com/ https://naturalatlas.com/) by the same small team who made the CoTrex app (https://trails

I highly suggest checking out Natural Atlas (https://naturalatlas.com/ https://naturalatlas.com/) by the same small team who made the CoTrex app (https://trails.colorado.gov/ https://trails.colorado.gov/) for Colorado Parks and Wildflife. A really fantastic team building some absolutely gorgeous topographic basemaps from publicly available data. Hopefully they'll find time to add a slope angle overlay at some point.