Why did vernal equinox on the ecliptic move westward?

Vernal equinox is a fixed point in the earth's orbit and cannot move westward. Newton's solution to the precession of the earth's axis is a firm denial of the westward shift of the vernal equinox! If Newton thinks that the vernal equinox can move westward, then Newton uses the tropic year when the earth rotates less than 360 to solve the precession.

Because the tropical year uses a natural timer, under the action of the earth tide, this natural timer lags behind the manual timer, shortening the time of tropical year. Of course, you can see that the solar terms are moving westward when you observe the shortening of time.