OpenTopoMap is what solves that issue for me. The contrast on that map is excellent.

It's a mostly a style for OSM with hillshading applied. The Friedrich-Alexander-Universität Erlangen-Nürnberg is hosting a web-based "preview" of it at https://opentopomap.org. https://brouter.de/brouter-web and https://bikerouter.de also have it as a selectable map layer, and it can also be added to OsmAnd.