According to your current description, it is a problem of insufficient pen power. Pen power is honed over a long period of time. It is recommended that you first think about how the center uses the pen, and then you can further understand the lower cone painting. Sand, insect-eaten wood, house fall marks and other brushwork techniques. This may be the question you need to solve right now.
Finally, there is no shortcut to practicing calligraphy. The key is to rely on your own diligent practice and thinking. No matter how well others think about the road for you, it belongs to others. Maybe it will be easier this time but harder next time. As long as you persist, you will always gain something.
To use ink, it is best to use grinding ink, or Yidege, or you can mix it with some water, depending on your preference.
Using ground ink can express the muscles, bones, flesh and skin of the characters. Don’t use too thick ink at this stage.