Is there any legal evidence that performing Fajr prayer on time is an indication of Allah's love, His choosing, and His granting of success, and does not waking up, despite taking the necessary means, signify that Allah does not love that person?

Maintaining acts of obedience, the best of which is congregational prayer, is a sign of Allah's love, pleasure, and guidance. Conversely, neglecting them indicates weakness of faith, and prayer is heavier upon the hypocrites. Some Companions' absence from غزوة (military expedition) or other events was due to a valid excuse, so there was no sin upon them. The same applies to one who is overcome by sleep for Fajr prayer after taking the necessary precautions. There is no negligence in sleep; rather, negligence is on whoever delays the prayer until its time has passed. Therefore, a believer should be keen on performing congregational prayer, and if he misses it due to an excuse, he must make it up immediately.