"Here are five takeaways from the summit:

Disillusionment with the US/West
The membership of Saudi Arabia, Iran, UAE and Egypt – Ethiopia and Argentina are the two other countries – in BRICS will take effect from January 1, 2024.
The enthusiasm for BRICS in the West Asian region signals that it no longer sees its relationship with the world through the eyes of the United States.. The weakening US influence in the region became apparent with the China-brokered Saudi-Iran peace deal earlier this year. Barring Iran, each of these nations has been a close US ally until recently.
....
Iran less isolated
A membership of BRICS gives Iran an opportunity to signal that the US attempt to isolate it has failed.

Iran has forged close ties with China (the two sides have reportedly signed a “25-year co-operation programme”) and Russia. With Chinese mediation, Iran signed a peace agreement with Saudi. The deal has stopped the fighting in Yemen, though the conflict in that country still awaits resolution.
....
A well-oiled BRICS
The grouping now has five of the top 10 oil producing countries, adding to its financial and economic heft. Saudi and founding members Russia and Brazil are respectively the second, third and eighth biggest oil producing countries (the US tops the list), while UAE and Iran are ranked seventh and ninth respectively. The three West Asian countries are key members of OPEC.
....
BRICS and blocs
Members of BRICS emphasise that it is not an anti-Western bloc, and speak about “strategic autonomy”, and multipolarity, and having their voice heard in the global arena. This appears to be the main attraction for the long waiting list for joining it, at last count 40 countries. Access to China is always good leverage in negotiations with the West. Interestingly though, the summit declaration affirmed the importance of US-Iran efforts to restore the 2015 nuclear deal (or Joint Comprehensive Plan of Action) “and hope for relevant parties to restore the full and effective implementation of the JCPOA at an early date”, appearing to distance itself from President Raisi’s belief that the US had nothing more to offer."

https://thewire.in/world/brics-expansion-saudi-arabia-oil-iran