Hi! There is currently no "easy" tool like Game Maker or GB Studio for making GBA games. The closest we have is Butano but it still requires good C++ skills.
Common software used for GBA dev includes
- A modern text editor such as VS Code
- The devkitARM toolchain to compile the code
- Aseprite for pixel art
- Tiled for building level maps
- Grit / Wingrit to convert pixel art to GBA compatible formats
- OpenMPT or MilkyTracker for music