Are bonus chest and starting map legal for speedruns? If so, which categories. I have never seen anyone use it, but it isn't a cheat. Probably a stupid question, and I'm sure the answer is no, but I was just wondering.

I've tried many times on multiple worlds to one-cycle the ender dragon. When it perches, I shoot the head, but then it flies away. I tried many times, but can never get it to work. If anyone has any tips, please let me know!