But it came to pass on the seventh day that they rose early, about the dawning of the day, and marched around the city seven times in the same manner. On that day only they marched around the city seven times. And the seventh time it happened, when the priests blew the trumpets, that Joshua said to the people: “Shout, for the Lord has given you the city! Joshua 6:15-16

After six days of walking once around the city, now they walk seven times around Jericho. On the seventh trip the shofar’s sound, the people shout, and the walls of Jericho fall.

God could have very well conquered the city on the first day, the second, or the fifth. He did not do it that way.
I’m not going to say I know the mind of God on this but perhaps His purpose was to show that faith and obedience in God give victory.

As you keep reading you discover victory turns to tragedy when you’re not obedient.
Joshua told the people not to personally keep any spoils of the city. One man disobeyed.
That caused Israel to lose the next battle against a numerically inferior city.

Faith and obedience in God gives victory.
Covetousness and sin distance you from God and brings death.