How can the heart be purified from hypocrisy to become a sound heart, especially with the feeling that the inability to perform Fajr prayer on time may be a sign of hypocrisy?

Fear of hypocrisy is a characteristic of the righteous. This fear should motivate further self-reflection and diligence in performing good deeds, not lead to despair of God's mercy. Heart ailments are treated by relying on God and supplicating Him, striving to seek Islamic knowledge, self-accounting and tending to the heart, and contemplating the afterlife. As for sleeping through Fajr prayer, there is no sin in it if the Muslim has taken measures to wake up, for the sleeping person is not held accountable.