I wrote my CHIP-8 emulator in C#, actually. I used the Godot game engine for rendering and sound (though I never actually got around to implementing sound). The language you write it in really doesn't matter too much unless you really care about performance, or if you want to do something fancier than an interpreter (like a JIT recompiler). I used this guide:

https://tobiasvl.github.io/blog/write-a-chip-8-emulator/

I haven't made a Gameboy emulator, just learned the assembly so I could modify some roms.