“Bunker Buster” technology is quite mature. Basically, a bunker buster bomb is a worn out 155mm artillery tube driven with enormous force against a reinforced concrete wall that fires a huge charge once its momentum is spent. The enemy can have several layers (false voids) in front of the ulimate target. You may have to cascade several rounds.
A huge advantage is that once the bunker is pierced, it helps contain and amplify the damage resulting from the blast.
you are thinking so much about the way Israel or the US will hit Qom but we all know that both of them have the ability to do it.
it’s not the way to attack Qom that matters its how to defend Israel and the American forces in Iraq after destroying Qom and how you are certain that the Iranian don’t have their nuclear bomb already, remember that the man who gave India and Pakistan their nuclear bomb is an Iranian scientist worked for many year in the Iranian nuclear program before working with Pakistan and Iran