Hi @Hongyi, for Linux regardless of if you are using ifort or gfortran you should be able to use VS Code + the Modern Fortran extension. Please use the pre-Release version and allow it to install fortls.
That should give you an IDE level debugging functionality with breaking points, hover, watch windows, stepping, etc. OpenMP threads should also work, but no MPI, conditional or functional breakpoint support.
FYI You will need to make sure you use Intel’s GDB version in your launch.json, see the docs for how to do that