This is we called Classic Tsundere.
NB:
Classic Tsundere: Refers to characters who are initially harsh, cold, or aggressive but gradually reveal their softer, more caring side over time. Their "tsun" demeanor dominates in the beginning, and the "dere" aspect is revealed slowly.
Modern Tsundere: Focuses on a more balanced mix of "tsun" and "dere" traits, often switching rapidly between them. This type can display their softer side sooner, sometimes even in the same scenes as their abrasive behavior.