Is one who misses Fajr prayer and wakes up after sunrise sinful, and what is its expiation?

If you did not set the alarm out of forgetfulness and not intentionally, then there is no sin or expiation upon you, for the Prophet, peace and blessings be upon him, said: "Indeed, Allah has pardoned my Ummah for their mistakes and forgetfulness." And it is obligatory to take the means to wake up for prayer.