"Just fine" for what? AGM88 is air-to-ground and manpads are surface-to-air. If you're implying that manpads work just fine instead of A-10s, you're wrong.
Geran-2 (which is Russian licenced Shahed drone) also carries air-to-air missile, so sending slow archaic manned airframe is just suicide mission (aka shaheed)
That is not a Shahed drone, that is a Geran-2 drone. Which is similar from the outside but not the same. Also Iran doesn't have stock of R-60s I think.