I ran Instant Meshes over a model of Mount Chimborazo and it did an okay job. Although the mesh was fairly uniform with its quads, the topology looked weird. Like the typographic equivalent of "rivers" running through the mesh. I decided to keep the imperfect topology, with some amount of decimation, because it looks better.

https://i.ibb.co/2nX8WfC/chimborazo.png

Retopology tools are discussed on a Blender forum:

https://blenderartists.org/t/best-auto-retopology-tool-ever/...

Have you tried them? What are your thoughts? What tool would you consider state-of-the-art?