Not sure I followed this, but yes after running set PATH=C:\msys64\mingw64\bin;C:\msys64\usr\bin;%PATH%, you’d expect gcc --version to return output like what I pasted above.
Do note setting PATH like this is not persistent. So once you close command prompt and open again or open new window, you’d have to set it again. You can either edit the env variables from UI or just use setx PATH "C:\msys64\mingw64\bin;C:\msys64\usr\bin;%PATH%" to have it persistent.
My guess is your rust installation is still msvc based. Once you get gcc --version to print the output than the error, I’d almost install rust for windows-gnu again for 1.14.0 and try a fresh build so cargo clean && cargo build --release and hopefully should be sorted.