Do my feelings of hardness of heart and distance from guidance stem from sins, and how can I strengthen my relationship with Allah despite this feeling, and how can I find righteous companionship and seek knowledge?

Sins veil the servant from Allah and cause a blackening of the heart. The cure for this is sincere repentance and replacing evil deeds with good ones. A sound heart and increased faith are achieved through constant contemplation of Allah's names and attributes, pondering the Qur'an, reflecting on death and what comes after it, visiting graves, accompanying the righteous, adhering to remembrance (dhikr) and supplication (du'a), and seeking sacred knowledge. Whenever you sin, repent and seek forgiveness, and soften your heart with the remembrance of Allah and the recitation of the Qur'an with humility and contemplation.