Now I think office writing is not only practical, but also suitable for practicing calligraphy!
There is a kind of pen that can be called "magic pen". All the pens are carefully polished and transformed by the boss. The handwriting is calligraphy. As long as you can write well with this pen, you can write well with calligraphy! (Different brands, but they are all good pens)
Rendering:
Taobao, you search for "hand polishing pen" as shown in the figure.