How can one return to Allah and remove the rust from the heart after deviating from commitment, and does seeking forgiveness revive hearts?

The door of Allah is open for a return to Him with sincere and immediate repentance from all sins, for Allah is Forgiving and Merciful. One who repents from sin is like one who has no sin. Repent sincerely and cease from acts of disobedience. Safeguard the obligatory duties and increase in voluntary acts. Seek help from the company of the righteous, remember Allah and supplicate to Him, and strive against your lower self. Reflect on the Hereafter, recite the Quran with contemplation, and occupy your time with what benefits you in your religion and worldly life, such as engaging in scholarly and da'wah activities.