When I was a freshman, I practiced Pang Zhonghua's regular script. I used to write slowly, and sometimes I couldn't remember my notes. I practiced Pang Zhonghua's running script in my sophomore year. I only talked about writing speed, and there was almost no improvement. In other words, practice writing-no matter what font you practice, the writing speed will not improve.
Writing speed depends on writing, such as taking notes, and you can copy a lot of homework when you are free.
In addition, I think the handwriting of several hard-pen calligraphers you mentioned is good, and I think Tian's is better. But there is a saying that "all roads lead to the same goal". I think as long as you practice well, the result will be similar. Also, it takes hard work to practice calligraphy. If you follow the picture on the copybook, it won't have much effect. Pang Zhonghua thinks it is enough to practice 3-5 words every day. My method is to practice only about 10 words every day. As long as there is a gap in the high school textbook, I will practice. This method is not good. I suggest you spread a newspaper on your desk and write on it when you think of it (mainly copying it against copybooks). It won't take a year and a half to make your handwriting enough for the exam.