Why isn't the lunar calendar the 24 solar terms?

Our lunar calendar is a lunisolar calendar. That is, it takes into account both the sun's and the moon's orbits. Among them, the 24 solar terms are based entirely on the return of the sun. So the days of the Gregorian calendar for each solar term are basically certain, while the days of the lunar calendar are instead very different. However, the lunar calendar is based on the moon's waxing and waning each month. As you know the solstice is basically always on the first day of the month, and the wang is on the fifteenth day of the month.

The lunar calendar is a yin and yang calendar: its years are divided into ordinary and leap years. In a leap year, there are thirteen months and twelve months in an ordinary year. Months are divided into large and small months, with a large month of thirty days and a small month of twenty-nine days, and the average calendar month is equal to one lunar month. The average calendar month is equal to one lunar month. Which month of the year is large and which is small is determined by calculation.

The lunar calendar is a calendar that takes into account the relationship between the sun, the moon and the earth. The lunar calendar does not take into account the Earth's orbit around the Sun, thus making the seasons not fixed and reflective of the seasons on the lunar calendar.