I suggest you practice with a brush and a hard pen, which will get twice the result with half the effort! Practice Yan Zhenqing's Diligence Monument in regular script, and select Wang Xizhi's Preface to Lanting and Preface to Saint Education as the running script. If you just want to practice pen writing, you can learn from Qian Peiyun, which is faster. Practice every day, stick to it and you will be decent! But if you want to practice writing, remember to write like that!
Pen writing and brush writing seem to have nothing to do, but practicing together will improve faster!
Come on!