CoMaps

I've tried OsmAnd, CoMaps (Organic) as well as Transportr - out of those OsmAnd seems to be the all around best one - it's still not ideal as it will often not find full addresses or just postcodes and it does have good public transit coverage in my experience but also struggles often enough to make it unreliable in a pinch requiring gmaps as backup. The UX is also a bit clunky but is super feature rich.

Transportr seems to be the best for public transit but coverage is limited and isn't available where I live.

CoMaps is the best UI wise but UX can be lacking (eg it doesn't have an origin destination bar at the top so if you're trying to navigate from a place you're not at you have to click search then the address then click on "route from" then go back and search for the destination then "route to" which is a hassle.) More critically it only has subways so no bus or rail which makes it a bit useless for me.

Also https://cycle.travel/map is really good for cycling but doesn't have an app so I use OsmAnd since it has so much useful customization (tho that may seem overwhelming to some)

also a good option if you want to ski or horseback ride around..