@peregrina2000 and I spent quick a bit of time discussing our different approaches to map apps, while walking the Lana a few months ago. There are some definite advantages and disadvantages of each app. While I initially hoped I could just find one app that did everything for me, I came to realize that using several apps was really not any different from using several features on a single app.
If all the following seems overwhelming, perhaps you are at a stage where the simplest single app is best for you. After you get more comfortable with that, you can always consider some of the following variations. If you are walking a popular route for which custom apps are available, they should suffice. The following is probably more relevant to detailed planning of less popular routes.
Google maps
Like most people, I use this at home and in Spain for up-to-date information on restaurants, hotels, business, etc., especially in towns and cities, or for quick estimates of distances for places that I don't have route maps for.
Organicmaps.app
This is an offshoot from the original Maps.me which I happily used in the past before they made some major changes a couple of years ago.
First, I download to Organic Maps on my phone, the set of "All Caminos in Spain" from the
Dutch association . They also have routes from elsewhere in Europe. I love having this master map for quick reference and day dreaming, and I also have it on Google Earth on my computer. When I am planning the details of a specific camino, I first go to the local Amigos website to see if they have a downloadable track and I compare it. I may or may not bother to keep a duplicate map - at least it informs me that the suggested route is the same.
What I really like about Organicmaps is the ease with which I can annotate the maps with my own information and comments. I can drop pins anywhere on the map (not just on a track) to show places of interest, accommodation (including contact info or any notes I want to add), places that might be very muddy in the rain, or even comments about where I found this alternative track.
Organicmaps is like my master atlas and personal reference guide.
Wikiloc
I use Wikiloc to
find alternative tracks to put on my Organicmaps for comparison. If I like the additional info, I leave the track on Organic and note where I got the track and its name. I also put the track on a Wikiloc list and make it available for offline use so I can easily access it on the Camino.
I use Wikiloc to record my daily walks, but I generally keep them private; since I'm always following another track, my own track is redundant for others. Something that Wikiloc does that I did not expect to like, was the beeping alert when you are following a Wikiloc track and go off-track. This was
very helpful a number of times on the Lana and I am a total convert to its use. (Maybe turn off the sound when you are wandering off the official track in a town.) However, you must have a Wikiloc track in order to use this. I suspect that most of the Camino associations have also uploaded their tracks to Wikiloc, so it is worth finding them from among the many other tracks.
I'm not sure that I agree with
@peregrina2000 that "the absolute best way to use it (Wikiloc) is to go stage by stage". If a multi-stage track is available, it is simpler, provided the resolution is adequate (as the recent tracks do seem to be). For the Requena-Lana, I used a single KML track from Valencia to Burgos that was available from the association and that was also found on Wikiloc. I found the accuracy of this single map to be just as good as the piecemeal maps of each stage, and I didn't need to fuss with different maps before starting each morning. I also had the track on Organicmaps with annotations for reference and comparison with route alternatives that I had found. However, I followed the track and recorded my walk on Wikiloc; you can do this recording and save your own track on a daily basis even if you are following a longer track. Even while following the Wikiloc track, I would occasionally switch to check/compare something on my Organic master map.
Some of the Wikiloc features might be available only if you have the premium paid version. However, the price is a very minimal, and it seems like a worthwhile contribution to a group that is doing good work.