Q: “Do you think a higher horsepower car or higher downforce car is more difficult to maximize EoB (End-of-Braking) to full throttle?”
A: Not really. It’s all about using the car’s braking, cornering, and acceleration capabilities appropriately, and that doesn’t really change from a low horsepower/downforce car to a high horsepower/downforce car. I do think it can be difficult to have the patience in the transition from EoB to beginning to apply the throttle in some cars. See, some cars require a slight hesitation to allow the car to finish rotating enough to be pointing in the right direction before getting on the throttle, and sometimes with a higher horsepower car, you have to hesitate a tiny bit longer.
The key is learning what you car prefers, and that is not easy in any car. It is simple! But not easy. Using segment times, data, timing video replays, making note of top speeds on the following straightaways, and outright lap times are the hard metrics to use. But you’ll learn nothing if you don’t experiment with the amount of hesitation between the EoB and throttle application, and the same is true if you don’t change up the timing and rate of release of the brake pedal. The combination of the brake release and the timing of going back to throttle is what you need to “play” with, while paying attention to the results.