Kagi has maps in browser, but not an app. I haven't used it much. Data seems to be from OSM, mapbox, apple and maybe google. Plus Wikipedia of course. Map layers are mapbox. I use OSMand usually so haven't given Kagi maps much of a go despite using Kagi daily. I’m not a heavy maps user so it would probably be good enough for me but “Legit” would depend on your requirements .