Yeah.. I am also aware of Captopo too.. GaiaGPS is one I looked at, and FarOut (based on info from Maddie and Tom: https://theadventuregene.com/australian-alps-walking-track/#navigation ) .
Google Earth Pro was 100% free for a while though, and I was more familiar with it. I used a OSM mapping layer on top
Yeah.. When you mentioned, it makes sense now.