Antimalware Service Executable is the core process of the default antivirus and antimalware service in Windows 10 and 11. This articile explains what the process does, whether your computer needs it, ...
If speed isn't an issue you could try Cygwin which comes with gcc which includes a fortran compiler. I mention speed because IMO apps running under cygwin are noticably slower than 'native' ones. And ...
You need to start using Windows' overlooked package manager.