I can't fully recommend any of the current range, because what I use is ancient, but you might find
Memory Map worth looking at. There's an Android trial on the playstore. IOS too I guess.
I use V4 (my maps are mostly from 2004) and gave up on upgrading because for years their pricing and general attitude was so poor. However, V6 is a much better looking deal and I might upgrade. I can certainly vouch for tracking using offline maps so no signal issues, their OS and A-Z maps which I find clearer and easier to read than eg Google or OSM, route planning, use on a PC with simple transfer to/from Android, and track splitting and joining so you can keep a track for posterity without showing the detour via a cafe, join days together or whatever.
My version doesn't have turn by turn navigation and it doesn't look like that's included, but on the odd occasion I've ever needed it I just use google.