There are lots and lots of GPS mapping apps out there. Instead of trying to learn the latest and greatest, I use the ones I used five years ago on my Android devices.
- Maps.me. They changed the name a few years ago, used to be called Maps With Me and they had both a free and paid version. I bought the paid version but I think it now is only free. Older versions allowed a large bulk download of maps, but the latest version did not appear to do that anymore. Now instead of selecting a state and telling it to download the entire state, with my tablet it would only download the maps if I moved the map on the screen in a fairly close setting to download parts of states. This app is for car travel, bike paths not shown. Has routing. The maps it loads now take up a lot more memory than the maps I loaded several years ago, perhaps that is why I could no longer do a bulk download.
- Soviet Military Maps. It has several different layers, I use the Open Streets Cycle layer which has topographic contours in metric units. The paid version allows a bulk download of maps. And on the bulk download you could set the resolution you wanted for detailed (close in) scales. This can keep a track or load a track in GPX format.
I only use these for planning, as my screen or tablet has a bigger screen than my dedicated GPS. I do not have a sim card in my phone, so I can only load maps when I have wifi. I often would load in the area where I intend to go while I was still at home, then when I got to the location I already had all that I needed.
There are several others out there too, but I am content to live in the past.
I also have an automotive type GPS for my truck, so I rarely use these Android apps.