Heat and thermal energy are closely related concepts, but they refer to slightly different things.
Heat is a specific type of energy that’s transferred between two objects or systems that are at different temperatures. It’s the energy that flows from a hotter object to a cooler one. For example, when you hold a hot cup of coffee, the heat from the coffee flows into your hand, making it feel warm.
Thermal energy, on the other hand, is not very well-defined. It is sometimes used to refer to heat. Other times it may refer to the internal energy or the temperature.
So while heat is a specific type of energy transfer, thermal energy is can mean different things.