There are two basic types of BMX bike:
Race
Park/Freestyle/Flat/Vert/Ramp/Street
Racing is racing. Race bikes are light, fast, and will not do tricks. They jump and pump in a fast forward manner. Carbon fiber does not like vertical drops or hard abuse. Race bikes are more specialized. You don't need a race bike to start racing, but it sure helps.
Freestyle is a broad term encompassing what many think BMX is. BMX originally was racing, then tricks came with it. The bikes of the time did both more or less. In the 80's the split between race bike and trick bike became a thing. Freestyle bikes are heavy duty meant for smashing, grinding, jumping, vert air, and doing crazy things. You can race a freestyle bike and it's fun, but it is slower and will want to jump everything since it was designed to do that.
Race Bike
Park/Freestyle Bike
Aluminum frame
Lighter, thinner tires
Customizable gearing
Rider position forward
Compare the frame angles
Designed for race tracks
Steel frame
Heavier, thicker tires
Micro gearing to keep it out of the way
Rider position upright
Compare the frame angles
Designed for skate parks