What is incumbent upon one who deliberately delays the Fajr prayer beyond its time, then repents?

It is necessary to warn against the impermissibility of delaying prayer without a valid excuse until its time has expired, due to Allah's saying: "Indeed, prayer has been decreed upon the believers a time-bound ordinance."

If you perform the Fajr prayer before sunrise, it is sufficient and considered an on-time performance, because the time for Fajr ends at sunrise. However, if you pray it after sunrise, it is considered a make-up (qadaa'), and there is no sin upon you if your sleep occurred before the time of prayer began. But some scholars believe that one must take measures to wake up, otherwise, sin will be incurred.

You must repent to Allah for delaying prayer beyond its prescribed time and strive to ensure that it does not happen again.