Which font is better for practicing Chinese characters? What kind of copybooks are better on the market?

Didn't say the font was better. Just say what kind of font you like. Although the fonts are different, calligraphers' handwriting is beautiful in both ancient and modern times.

If you learn conjoined characters, you should find a running script or cursive copybook to learn them.

If you don't want to practice writing, but just want to write practical words, I recommend Xi Shu's practical word practice method. He standardized some strokes, so he could learn how to write practical words.

But if you want to write as beautifully as an ancient post, you have to learn from the famous posts of the ancients. For example, the calligraphy posts of the four great masters Wang Xizhi and Su Shi. Or learn the modern running script of Tian Yingzhang and Honggen Shen.

The fonts are all different, depending on whose handwriting the landlord likes. There are many calligraphers throughout the ages, and there is always one suitable for you. O(∩_∩)O~