First there was Osmand. AKA OSMAnd or officially OsmAnd.
It was was powerful but complicated. Normies had never heard of it and preferred Maps.me, a user-friendly alternative with an opaque business model. Then something at Maps.me turned sour and the more privacy-minded normies turned to Organic Maps. Then something at Organic Maps turned sour and some of them moved to CoMaps.
During all this time (literally 15 years), Osmand improved steadily and became more powerful than ever. Even the UX got (a bit) better. It is by far the best mapping app, either FOSS or commercial. And yet somehow it continues to languish in relative obscurity.