A lot of people are seeing this either as a surrender on Iran's part (Basijis, communists, South Asian pro-IR types) or a surrender on America's part (neocons, Zionists). It's neither. It's a smart convergence of interests and the culmination of efforts within Iran by sovereignty-minded YET pragmatic elements that sought to return Iran to its traditional role as a balancing middle power. According to the realist school of international relations, middle powers like Iran are not so dependent that they can opt for a vassal strategy, yet are not so independent that they can vie for great power status. What they do is they maximize their own utility by way of balancing other great powers. This is what successive Iranian governments did since the 19th century; some failed, some succeeded.
For Iran, what began with the 1979 Hostage Crisis essentially was the breaking of this pattern; Iran repudiated the West (and thus the "international community, ergo half the world) and removed from possibility this balancing dynamic. It sought instead of carve out a form of regional hegemony through influencing the Arab street and edging closer to non-Western great powers like Russia and China (this is more post GWOT). It resulted in maximum pressure sanctions and a trajectory that would have accelerated regime entropy and threatened the country's viability. The less ideological, more prudent types within Iran's establishment saw this clearly and while just as sovereignty-minded as the revolutionaries, battled within the ruling class over which direction the country should go in. These types envisioned Iran's sovereignty within the historical balancing dynamic, emphasizing deterrence via economic power and integration. The more revolutionary types emphasized deterrence via military posturing and carving out a "Shi'ite crescent". Both sides agreed on missiles, proxies and force projection, but differed on endgoals. Pragmatists saw integration into the world order as creating incentives that would ensure the survival of the state, while revolutionaries saw state survival as a matter of hard power. Furthermore, the role of oligarchs and the IRGC industrial complex weighed heavily on both political cliques. And yet pragmatists prudently realized that the very viability of the nation-state would be threatened if people lost their attachment to Iran; this was a matter of basic human needs being met and economic opportunity. This, in my opinion, proved to be the wiser choice given the constraints imposed by the West and the unreliability of allies like Russia.
In history and politics, governments, rather than being monolithic entities, are often composed of competing elite circles and interests. The Islamic Republic is no different; even autocratic dictatorships have varying nodes of power that the autocrat balances. Likewise, the United States also has its competing cliques in defense, intelligence, energy and political circles, and what we saw over the past 20 years is the emergence of cliques in both countries that saw it prudent to introduce a new paradigm between the two countries. It's hard to understate how important Iran's integration is to both the Iranian state and to the global economy, as well as to the West. And yet this does not mean Iran is abandoning China or Russia. It is merely settling into a new dynamic where both countries will have no choice but to have a less lopsided relationship with Iran, by virtue of Iran's freedom to balance varying nodes of power on the international stage.
It's not a capitulation on either side. It's a victory for all parties involved.
Iran’s President, Pezeshkian, in reaction to the message of the Leader:
“The message of the Leader is the roadmap for safeguarding national interests in the course of negotiations; we consider ourselves committed to implementing his concerns and guidelines.
Obviously, I, as the President and Chairman of the SNSC, along with other members of this council, consider ourselves committed to giving maximum attention to His Eminence's concerns and safeguarding the rights of the Iranian nation and the resistance front.
Undoubtedly, the red line for officials is national interests and preserving the dignity, honor, and power of the brave Iranian nation, and with the negotiation team's utmost attention to the details of the talks and confident hope in the grace and favor of the Almighty, a great victory will be achieved. God willing.”