How to practice hard pen calligraphy?

I wonder why there are so many problems with regular script that no one even cares about running script. Is learning regular script for writing regular script? When can I use it? Isn't it more attractive to slap a few words casually? Or if you learn regular script well, you can run it. If you think so, I may not be talking about people, but traffic charges. Tell me about the process of practicing calligraphy. First of all, I haven't asked the teacher or even been taught by anyone. Secondly, I haven't read an inscription systematically and completely. Finally, many people who have studied it have written that it takes time. What's more, Wang Xizhi's Preface to the Lanting Pavilion and all kinds of notes can be seen in Wang Xianzhi Luoshen House and Mi Fei. As a small seal script in Wei and Jin Dynasties, Luo Shenfu is more elegant and less disciplined. As a basic script, mastering the structure is not friendly enough. I have always stubbornly believed that it is feasible to run regular script directly without practicing regular script. However, what is necessary for the understanding and teaching of running script? That is, writing regular script quickly is probably what most people want to practice, that is, how to write a good running script on the basis of regular script, or why I feel that regular script has improved a little, but as before, many people can't master this process well. This will be said in a big space later, and there is another one that has little to do with regular script, such as the most classic preface to Lanting, which emphasizes change and improvisation, and every word is a kind of re-creation when writing. This is a running script that is not bound by regular script. Compared with regular script, it can make the creation more free after writing faster. In fact, cursive script is not so free, and most of the structures are solidified.