Is someone who performs all prayers after their due times considered to have abandoned prayer, and are there any statements from scholars that support this?

A Muslim is not permitted to intentionally delay any prayer past its prescribed time. Whoever does so without a valid excuse is, in terms of sin and transgressing boundaries, like one who abandons prayer, even if he prays it after its time has expired. Whoever abstains from performing prayer is not to be left alone; rather, he is to be threatened and beaten until there remains time enough for one rak'ah. If he still does not pray, he is to be executed by the sword as a legal punishment, not as an act of disbelief, according to the Malikis. Delaying a prayer beyond its time without a valid legal excuse is considered, in essence, an act of abandonment. Therefore, whoever delays prayers beyond their times and encourages such behavior is to be called upon to repent. If she repents, well and good; otherwise, her case is to be brought before the ruler to separate her from her husband, and the prescribed legal punishment, which is execution, is to be carried out against her, based on the saying of the Prophet, peace and blessings be upon him: "Whoever changes his religion, kill him."