First and foremost you conflate Hezbollah, Alewites and Iraqi shias and shias generally with Iranians. This is disponest and therefor your claim Iran colonizing and taken over oil Fields is not true. They are doing same thing as US and Saudi is doing for their allies in the region, supporting them.
Using your terms Saudis have colonized Bahrain and Yemen together with UAE. They have supported a military dictatorship in Sudan and also bad actors in Somalia. They have tried to ”colonize” Qatar but failed. Israel is basically an apartheid state that is destroying the life of all Palestinians.
Iran supporting other entities which are lobbying missiles into Israel and Saudi Arabia is perhaps true. Yet it was Saudis and to some extent US who supported Saddam during Iran-Iraq war. A war where Iraq fired lots of missiles on top of Iran and even used chemical weapons against Iran. You conviently forgot about this war.
No matter how justified US is maximum pressure won’t work if your are emboldening your enemy and treating your own allies like shit (see any European nations lining up to support US?).
The only country that sanctions worked against was South Africa, but in that case it was against an apartheid state that was highly impopular both Inside and outside the country.