GCC (including G++ and Gfortran) on Windows is available via several means. We generally prefer MSYS2 for using GCC and numerous libraries with pacman package manager. MSYS2 and WSL have active and competent development teams.

WSL

recommended, gives Linux system

MSYS2

recommended, well-maintained

Cygwin

usually WSL is preferred instead for better performance

TDM

usually MSYS2 is preferred instead