A scenario in which Emperor Hirohito refuses surrender and keeps the war going seems unlikely for a number of reasons:

1. In June 1945, after receiving bleak reports about the state of the Japanese military and its defense preparations, Hirohito had already indicated his desire for the war to end as soon as possible. (His commanders and ministers disagreed on how to accomplish this; some attempted to pursue a Soviet-mediated settlement, while others continued to push for a final battle on the mainland, which would supposedly compel the Americans to negotiate a peace.)

2. The atomic bombings and invasion of Manchuria again convinced Hirohito of futility of prolonging the conflict. At the meeting of the Supreme War Council on 9-10 August, he personally intervened to break the deadlock over whether to accept the Potsdam Declaration, expressing here his belief that Japan had no hope of successfully fending off an invasion of the mainland and that further resistance would only bring more suffering upon the Japanese people.

3. In August 1945, with the Japanese civilian population experiencing severe food shortages, the military had stockpiled just enough rations to sustain their forces in the homeland for a few more months. (Food imports from the United States helped prevent mass starvation following the surrender.) Note also that Hirohito himself appears to have feared the possibility of social upheaval, which could pose a threat to the imperial institution.

Sources:

Sadao Asada, "The Shock of the Atomic Bomb and Japan's Decision to Surrender: A Reconsideration," Pacific Historical Review 67, no. 4 (1998): 477-512.

John W. Dower, Embracing Defeat: Japan in the Wake of World War II (New York: W. W. Norton, 1999), 89-97.

Edward J. Drea, In the Service of the Emperor: Essays on the Imperial Japanese Army (Lincoln: University of Nebraska Press, 1998), 145-153, 208-211.

Edward J. Drea, The Imperial Japanese Army: Its Rise and Fall (Lawrence: University of Kansas Press, 2009), 249-251.

Richard B. Frank, Downfall: The End of the Imperial Japanese Empire (New York: Penguin, 1999), 271ff., 350-355.

Tsuyoshi Hasegawa, "The Atomic Bombs and the Soviet Invasion: What Drove Japan's Decision to Surrender?" Asia-Pacific Journal 5, no. 8 (2007): https://apjjf.org/-tsuyoshi-hasegawa/2501/article.html.

Stephen S. Large, Emperor Hirohito and Shōwa Japan: A Political Biography (London: Routledge, 1992), 123-126.

Emperor Hirohito had only a minor say within the Supreme War Counsel, and was the tie breaker for peace. The Supreme War Counsel was essentially split evenly between surrender and continuing the war against America and China. Generally, the army was for continuing the war to get a more favorable peace, and the navy was for surrender. This had to do with their differences in success and fighting capability. The navy had lost its gambit of a short war for an advantageous peace and knew the futility of continuing a war with America. But, the army thought it could bloodlet America in a successful defense of the Japanese home islands, while it negotiated with Stalin as an intermediary. So, surrendering with conditions was the goal, so yes they would have eventually surrendered, but how long they would fight and if they would surrender without conditions was the question.

Hirohito was called to break the tie in votes with the Supreme Military Council. It is important to remember that no Japanese unit of any size had surrendered during the war, they always fought to the death. Therefore, many in the army could not even believe the emperor had surrendered, and it required the emperor's family to tell them to stand down. It was no surprise that a group of radical officers had attempted to put the emperor under house arrest before he could broadcast his speech. He was a god to the Japanese, but people high up knew that they could simply walk into the palace and physically take him. They were not so delusional as to think he had some kind of magic power to stop them. Also, the emperor could be replaced with a different family member. Hirohito was not the only one in the imperial line, and emperors throughout history, and even Hirohito himself at times, had to contend with potentially being replaced. Anyways, the coup failed when they could not find the emperor or the surrender announcement, and once it was broadcast, there was no chance of it succeeding, so they committed seppuku.

So, if the emperor had wanted to continue the war, it certainly would have continued for a time. People will cite the discontent of the population and the army's food supply(and other lack or resources), but America had sure plans to invade if there was no surrender. It is questionable that if America had invaded, that the army would have laid down their arms with the enemy on their shores due to their material situation. The army estimated around 20 million total casualties, civilian and military, amounting to a quarter of the Japanese population. That is the realm of casualties that was considered acceptable by the army high command let alone the more radical junior officers, so you can understand their mindset when they say "death before dishonor." So no, food deprivation would not have made them surrender, because the army had already considered that possibility/eventuality and accepted it. Moreover, the US went with invasion instead of prolonged blockade to end the war as quickly as possible. Also, the population was unlikely to have risen up with a foreign "invader" on their shores and also while they have no means to rise up against the military. But this is a hypothetical in history ,and so is based a lot on guesswork and opinions.

One caveat though, the invasion of Manchuria had came as a blow to the army's invincible facade, and had destroyed the army's method of gaining a favorable peace by using Stalin as an intermediary to negotiate with the Americans. It also scared the Japanese with the threat of a Soviet invasion of Hokkaido. It is hard to fully know the effects of the Soviet invasion of Manchuria on the army's overall plans because the time between the invasion and surrender was only a few days. However, it destroyed their hopes at a favorable peace and helped turn the tide with the atomic bombs and Hirohito to make peace possible. There are 5 theories surrounding this influence to surrender that historians themselves debate today. However, considering that Hirohito was the final say in surrender, it is hard to imagine it happening without him wanting it, especially if the fatalistic elements in the army had been asked by the emperor to die before surrendering, which is what they did up until that point.

It is hard to predict to what extent the war would have continued, but a US victory in Operation Downfall was questionable at best. How long would the army had gone with the emperor encouraging them, especially considering their fatalistic beliefs and worship of the emperor? I think it would have led to the 20 million casualties the Japanese high command had predicted, due to an invasion by America. America had chosen invasion, and not blockade, for the Japanese, so it would have gone on to that, there is no dispute that I have seen. The invasion would likely galvanize the populace of Japan into fighting the war and especially the military into continuing it. The Soviets potentially invading may have relieved some of that, but it is hard to predict to what extent as they were still securing a position in Manchuria even through the surrender announcement.

The army fought to the death when asked to before. Many fatalist officers in the army wanted to fight to the death, even disobeying the emperor to attempt to do so. Therefore, if Hirohito had encouraged war, it is hard to imagine the military laying down as the army high command still wanted to continue the war. He was the tie breaker for peace, and even his family was necessary to communicate the surrender orders to the army so they would listen. It is hard to imagine that it wouldn't have gone on to a bloody invasion.