The Wii U is from 2012 but the homebrew scene is surprisingly active and the toolchain (devkitPro) is well-maintained nowadays. At least that is my impression after developing some homebrew myself.

The interesting parts: cross-compiling C++ with devkitPro, using SDL2 on a console target with basically no documentation and debugging on real hardware without a proper debugger. Most of the resources you'd normally reach for just don't exist for this platform, so a lot of it was reading source code and trial and error.