How much money is ‘enough’? However much I earn, the target just keeps moving further away.

The target keeps moving because it is built to move. Once that is clear, most of the anxiety in the question loses its grip.

The heart was made so wide that no amount of gold fills it. That is not a defect in you, it is how we were made. Our master, peace be upon him, described the ache plainly:

“If the son of Adam had a valley full of gold, he would long to have two, and nothing fills his mouth except dust; and Allah turns in mercy to whoever turns to Him in repentance.”

The Prophet (peace be upon him), Sahih al-Bukhari (6439) · meaning

He is not scolding, he is describing, and he ends by opening the door of return. So stop waiting for the outward number to say “enough,” because it never will. Those who study how people think about their earnings notice the same pattern: as a person’s income rises, the figure they name as “enough” rises along with it. The number keeps moving because it is the heart doing the measuring, not the ledger.

And the Qur’an shows where this counting leads if it becomes the whole of a life:

“The mutual competition for increase distracts you, until you visit the graves.”

Qur’an, At-Takathur 102:1-2 · meaning

So where is the fixed point that stands still while the target flees? It is contentment, qana’ah, a richness that lives inside and does not move. Our master, peace be upon him, handed us the true measure:

“Richness is not in the abundance of possessions; true richness is the richness of the soul.”

The Prophet (peace be upon him), Sahih Muslim (1051) · meaning

You need not stop earning, and ambition is not a fault. Keep working, keep providing, enjoy the good Allah gives. Only let gratitude, rather than the next figure, be where your heart actually lives. The one who can say “alhamdulillah, this is enough” has already arrived at the place everyone else is still running toward.

One small step: Tonight, before sleep, name three provisions Allah has already placed in your hands, and say “alhamdulillah, this is enough” over each one.