How can one overcome the continuous feeling of unease, anxiety, and fear, as well as the sense of being distant from God during acts of worship and losing the sweetness of closeness to Him, which leads to emotional stagnation and depression, despite adhering to acts of obedience and drawing nearer to God?

Fear of showing off (riya') is a good thing, but exaggerating it is blameworthy if it reaches the point of despair. Therefore, one must combine fear with good expectations of Allah and hope for His grace, while contemplating His attributes of beauty, such as mercy and gentleness. What you feel might be a satanic whisper (waswasah) aiming to deter you from doing good deeds. Hence, you must be wary of it, turn away from it, and strive in supplication.