Does the accumulation of sins prevent the glorification of Allah in the heart, and is what the questioner experiences of waxing and waning in his relationship with Allah a test, or hypocrisy, or an incomplete Tawhid and faith?

Allah forgives sins, no matter how numerous, for whoever repents sincerely. For indeed, Allah the Almighty says: "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.'" The servant must correct his repentance and remain steadfast upon it, and make his remembrance of his sins a motivation to increase good deeds, for good deeds erase bad deeds. What the servant experiences of turning towards and away from Allah is a test, so that Allah may distinguish the truthful from the liar. The successful one is he who follows his good deeds with more good deeds, and his bad deeds with seeking forgiveness and rectification.