We shouldn’t have attacked Iraq or Afghanistan. The premise for the war in Iraq was that Saddam was harboring weapons of mass destruction. That was a flat out lie. The Iraq war and the power vacuum it created led to the creation of ISIS.
Afghanistan had elements of Al-Qaeda present. The Taliban tolerated them. We should have hunted bin Laden there and hit Al-Qaeda where we could find them, but toppling the government was mostly useless and we ended up needing to get the hell out of there after spending $2 trillion dollars, only to have the Taliban return.
Should we have attacked Saudi Arabia though? Absolutely. We should have actually done regime change there and maybe even helped ourselves to the oil revenues to cover the costs of 9/11 and our military. Our presence would’ve also helped modernize their medieval society in ways beneficial to the Middle East.