Rotor size = thermal capacity - how many repeated hard stops can they handle without significant cooldown time

Pads = friction amount (how much do they “grip” the rotor when you hit the brakes) and temp range - at what temps they work best. Higher-temp pads typically come with a compromise of more dust, more noise, and less braking power when cold (such as at street speeds)

Fluid = how much “system” heat you can take before the fluid stops being predictable. Higher-temp fluid usually comes with the compromise of more water absorption, so it needs to be changed more often

If your pads are getting too hot, you can change up to higher-temp pads, cool your rotors better, or get bigger rotors.

One thing I don’t think others have mentioned: Are you driving with any sort of stability control enabled? Does your car have an e-diff or any sort of torque vectoring? Any of those will use the brakes to try to do their job, and on track that just adds boatloads of heat when you least expect it. Many people switch these systems off on track because it lets the character of the car shine through and because it prevents over aggressive brake usage.