They are different maps of the same territory: you.
Western astrology uses the tropical zodiac (Sun's position relative to Earth's seasons). BaZi uses the solar calendar (based on the Sun's longitude) plus hourly pillars. Astrology emphasizes planetary aspects and houses; BaZi emphasizes elemental balance and timing cycles.
Neither is "more accurate." They excel at different things. Astrology often shines in psychological depth. BaZi excels in practical timing, career alignment, and understanding your relationship with money and power. Many people use both together.