from where?
Kharg island can be hit from at least 25 different cities with FPV drones. These are mostly small communities within 40 KM of the island. They are within attack range.
Within 200 KM, there are hundreds of cities where Shahed drones can be launched to strike specific coordinates on Kharg island.
Check Google Maps. Attack sources are obvious. No doubt there are others which are not so obvious.
Does the IRGC have the drones? Can they get them into launch positions? Can they coordinate repeated strikes across dozens of launch sites? They probably cannot launch twice from the same position. But they only need to hit US Forces on a first wave strike. Any significant American casualties will instantly halt all political support for continuing the war. That is what the IRGC is counting on.
Maybe they do not have enough missiles and drones left to counterattack. That is what we are counting on.
We have hit over 10,000 sites in the last four weeks. But a "90% reduction in Iranian missile/drone attacks" is really not good enough. We need to get their attack capability down to zero - at least within 200 KM of any island landing. That is because we have no effective defense capability against FPV drones. We do have some capabilities against the GPS guided drones like the Shahed.
Bunching up a lot of US troops on an island makes them convenient targets. It is a very big risk.
The best defense we have now against missile/drone attacks is to destroy them before they can be launched. That means constantly blasting anything in the coastal area that could hide or carry a missile. It is a very big area. We might be short on bombs to cover it all.