miitomo on 64-bit-only devices is nearly (im)possible, here is why
a lot of people still ask/suggests if miitomo could be brought back on modern android phones, especially 64-bit devices. after checking out how the game is built, the truth is that it's not impossible, but it's so impractical that it's pretty much out of reach for regular modding or revival attempts.
the game itself is built with cocos2d-x engine, which means that most of the important logic is c++ code that's been compiled into a 32-bit armv7 library. that library is the heart of the game. on modern 64-bit android devices, those 32-bit libraries can't be loaded at all, which immediately blocks the game from running.
there's also no official 64-bit version of miitomo. if there isn't a prebuilt arm64 version of the native code, the only way to make it run natively would be to port it. that'd mean reverse engineering the main native library, understanding how the engine and game systems were implemented, and rebuilding it for arm64. you can't just recompile or make small patches to fix this. it's basically like rewriting most of the game without the source code.