I have grown quite fond of the OS app. Granted it requires a subscription but you get UK coverage with the option to switch between mapping, aerial imagery and a “standard” map as well as 3D aerial imagery and paths within national parks. I like the “snap to” feature for route plotting although at the moment it only works in national parks.
You also get the option to download other folks’ routes from it as per ViewRanger but they are free (once you have paid the sub).
It still has a way to go in some respects though - editing a previously published route is a pain. VR is better for that.