Can Allah be so angry with a servant that there is no pleasure after it, even if he repents and regrets? And will a pedophile who repents enter Paradise? And what is the ruling on seeking knowledge 24 hours a day with slight seclusion from people?

Allah's wrath, after which there is never any satisfaction, and His satisfaction, after which there is never any displeasure, occur in the Hereafter for the disbelievers who are eternally in Hellfire and for the monotheists who are in Paradise, respectively. As for this world, Allah is wrathful towards disbelievers and disobedient people, but if they repent, believe, and He becomes pleased with them.

Pedophilia (sexual obsession with children) is not merely an involuntary psychological disorder; rather, it is an addictive major sin from the major sins, related to a person's will and lust. A person is not born with it; instead, it is a pathological behavior in which a person follows his desires.

The cure for this sin and others is through fearing Allah and acting in obedience to Him, and by increasing in repentance and seeking forgiveness. Allah forgives a repentant person for any sin, including disbelief, for His saying, the Almighty: (Say, "O My servants who have transgressed against themselves [by sinning], do not despair of the mercy of Allah. Indeed, Allah forgives all sins. Indeed, it is He who is the Forgiving, the Merciful.") Az-Zumar/53. This verse is specific to those who repent, while the verse (Indeed, Allah does not forgive association with Him, but He forgives what is less than that for whom He wills) [An-Nisa: 48] is for those who do not repent.

Devoting oneself to seeking knowledge is permissible if the knowledge is a means for worship and inviting to Allah, and if it does not hinder one from fulfilling his duties towards himself and his family.