Box64's documentation is just on installing the Wine x64 builds from winehq repos, because most arm repos aren't exactly hosting x64 software. It's even possible to run Steam with their x64 Proton running Windows games. At least on ARM, not sure about RISC-V.
Wine's own documentation says it requires an emulator: https://wiki.winehq.org/Emulation
> As Wine Is Not an Emulator, all those applications can't run on other architectures with Wine alone.
Or do you mean provide the x86_64 Windows API as a native RISC-V/ARM to the emulator layer? That would require some deeper integration for the emulator, but that's what Box64/box86 already does with some Linux libraries: intercept the api calls and replace them with native libraries. Not sure if it does it for wine