How long does it take to learn regular script in Liu style?

With your current skills, you will continue to attack and improve more and more slowly, and even feel like drilling a dead end. You can change copybooks, such as seal script and running script, but don't give up Liu Kai completely. Write another font for a while, and then write Liu Kai back, which will make you feel suddenly enlightened. As the saying goes, stones from other mountains can attack jade, that is, things always meander forward and spiral upward.