The true ultimate way to be fast is unknown. It can be due to just being on the computer way too many times, or just a natural affinity due to being born in a time where you had computers around you.

When my fingers hurt after too much time on the keyboard, I... take a break. My fingers rarely if ever actually hurt after too much time on the keyboard, but if you happen to have it happen, honestly just take a break. Here's a tip, you can't hurt your fingers if all you're doing is watching YouTube, haha.

What really helped me improve my typing speed is... keeping your posture. Always keep your hands in the normal layout that is supposed to be, pinky on a, ring on s, middle on d, and pointer on f, for your left hand. Do the same for the other hand but keep the pointer on J and just let the rest of your fingers minus the thumb on the keys after J. Aka, J K L and ; Depending on if you're left or right handed, you'll end up pressing space with your right or left hand. Me, being left handed, I end up finding myself pressing space with my left thumb and keeping my right hand a bit more spread out. Of course, not everybody can have fast fingers, it takes practice like everything. Big words will slow you down, it's natural. Some people can just type fast. I assume I probably got my fast typing from being a loser and playing video games. That's all I can really say for how to be fast and accurate