What is the solution to the problem of fearing Hellfire, death, and the Day of Judgment, and the resulting inability to enjoy life and the fear of sins, despite adherence to acts of worship and repentance from sins?

May Allah bless you in your repentance, and I hope from Allah Almighty that He accepts it, for He accepts repentance from His servants and forgives sins. Remembering death and the afterlife is commendable, but in moderation, so that it does not hinder you from performing your duties, nor lead you to obsessive thoughts. Indeed, Satan may push the believer to exaggerate in worship until he deviates from moderation. This fear should be a motivation for righteous deeds, accompanied by hope, and should not lead to despair of Allah's mercy. For the rectification of a believer lies in the convergence of fear and hope in his heart.