It should be: Instead of digging many wells, it is better to dig the deepest well.

This sentence means that it is better to spend a lot of time and energy digging a shallow well that may not produce water than to spend the same time and energy digging a deep well. Because digging for prospects is likely to be a waste of time and energy, but in the end it will be thankless. But if you dig out clear scenery, as long as you put in the time and energy, you will definitely be able to make ends meet. Its meaning is to just concentrate on doing one thing and don’t do it half-heartedly. There is also a famous saying that digs many necks to dig a well. In fact, this famous saying means it is better to dig a deep well than many shallow wells.