Why did the Prophets pray to be among the righteous, and not pray to be among the martyrs or the truthful, even though Allah Almighty joined them with the righteous?

The words you read are the saying of some scholars in interpreting the verse: {And whoever obeys Allah and the Messenger – those will be with the ones upon whom Allah has bestowed favor of the prophets, the steadfast affirmers of truth, the martyrs and the righteous. And excellent are those as companions} [An-Nisa: 69]. The Siddiq (steadfast affirmer of truth) is one who is excessive in truthfulness or affirmation, and whose actions confirm what he says with his tongue. They are the highest in rank among people after the prophets. As for the martyrs, it was said that they are those who were martyred in the way of Allah, or those who were martyred on the Day of Uhud, and among them were mentioned Umar, Uthman, and Ali. The righteous are all the Companions, or the generality of the righteous in the nation of Muhammad. As for some prophets asking Allah to join them with the righteous, the righteous here refer to the previous prophets or the people of Paradise.