When I compare my worship to someone who prays far less than me, I feel spiritually ahead of them. Is this quiet superiority harming me?

You have noticed this while it is still small, and that is the useful part, because a comparison caught early can be set down easily. The feeling itself is nothing rare. It brushes past people who pray regularly, which is why it is worth understanding rather than panicking over.

What you are describing is a quiet measuring, a sense of standing a step ahead. The trouble is not that your worship is worth little. The trouble is that the measuring was never ours to do. Allah alone sees the whole picture, and He tells us plainly not to weigh ourselves:

“So do not claim yourselves to be pure; He knows best who is righteous.”

Qur’an, An-Najm 53:32 · meaning

Read that as a relief more than a rebuke. The scale was never in your hands, so you can put it down. And the Prophet, peace be upon him, showed us how much weight even a small looking-down carries:

“It is enough evil for a person to look down upon his Muslim brother.”

The Prophet (peace be upon him), Sahih Muslim (2564a) · meaning

The scholars pass down a saying that turns the usual thinking around. A person weeping over his shortcomings may be nearer to Allah than a worshipper who has grown pleased with his own prayers, because what is weighed is not the count of deeds but the state of the heart that offers them. So the fullness of your worship is itself a gift, and the way to protect it is to keep it low and grateful.

The man who prays less than you is not beneath you. Allah may be drawing him near by a road you cannot see, a private grief, a hidden humility, a kindness nobody knows about. And your own prayer, which is real, stays sound as long as the gaze stays lowered and the thanks stays with it, thanks that you were given the strength to pray at all.

So keep the deeds, and let humility walk beside them. When the comparing thought comes, turn it into two things, gratitude for what you were given, and a short prayer for the other person. Nothing is lost that way, and the thought stops working against you.

One small step: Tonight, quietly make du’a for one person you have ever felt “ahead” of, asking Allah to raise them and accept their worship, and say nothing of it to anyone.