Praise be to Allah, and peace and blessings be upon the Messenger of Allah. To proceed:
It is not correct to say that everyone who dies during Ramadan enters Paradise without reckoning or punishment. There is no authentic evidence granting death during Ramadan this particular virtue.
It is authentically established that the Prophet ﷺ informed us about seventy thousand members of his Ummah who will enter Paradise without reckoning or punishment. He described them as those who perfected their reliance upon Allah and avoided certain practices, saying:
“They do not seek ruqyah from others, they do not believe in bad omens, and upon their Lord they rely.” Narrated by al-Bukhari and Muslim.
The hadith does not state that those who die during Ramadan are among them.
Rather, there is a special virtue for the one whose life ends with a righteous deed, including fasting. The Prophet ﷺ said:
“Whoever says: ‘There is no god worthy of worship except Allah,’ seeking the Face of Allah, and this is the last thing he does, will enter Paradise; whoever fasts one day seeking the Face of Allah, and this is the last thing he does, will enter Paradise; and whoever gives charity seeking the Face of Allah, and this is the last thing he does, will enter Paradise.” Narrated by Ahmad; authenticated by al-Albani.
This indicates that the virtue is connected to faith, righteous deeds, and a good ending, rather than merely dying during Ramadan.
Therefore, whoever dies during Ramadan while being a believer who was fasting, or whose life ended with a righteous deed, we hope that he will receive goodness and have a good ending. However, it is not permissible to state with certainty that he will enter Paradise without reckoning merely because he died during Ramadan.
And Allah Almighty knows best.