I post two screenshots (the second is in the following post due to forum restrictions) of the same topographic area taken from my Samsung Galaxy S10e to describe my problem
As you can see, ,if I use Openstreet maps, the writings of paths and mountains are quite tiny and difficult to read unless I zoom in to max resolution, while with Opencycle maps thay are clearer.
Is this an issue that I can fix playing with app settings, or there is nothing to do but to accept Openstreet maps as they appear?
You can change the level of detail or screen density in MyTrails > Preferences > Visual > Map size.
Regarding the required API Key, see this FAQ.