Thanks, Dmitry.
I have been doing copywork off and on for nearly 4 years now. It's not a daily practice for me as I do not write daily, but it is something I use to spark inspiration or if I feel that I've hit writer's block. It's a way to get me to write and in the process, practice and grow.
For tools I use Scrivener. I keep a project that I use to write short stories. A sub-folder in this project is dedicated to copywork; there are paragraphs and chapters of stories of copied.
A bonus regarding tools is that Scrivener has some linguistic functions that let you see a breakdown of dialogue, adverbs, etc. That is always interesting to see. I also like to take the work I copied and throw it in a grammar tool like grammarly or ProWritingAid and see what errors it comes up. While we can't the original draft of the work, we can see what was left behind and ask why they left that word, or that lack of punctuation. Sometimes you'll find an editorial decision that the author and editor purposely ditched grammatical rules to emphasize a character or moment in a story.
Lastly, I would say that the only difficulties I faced when first starting was to look at the work of the authors I am copying and ask "why do I even write?" It's important to know the goal. No matter the goal, you should always compare yourself to yourself. That will show growth as it may be invisible to see otherwise.
I think you're going about it in a fantastic way. Practice over time will definitely improve your writing, but engaging with the text will give you deeper instruction as you can ask what that word meant, or explore how it is used. I just find the practice of copywork to be fun and educational.
Good luck on your copywork sessions! Let me know if there is anything else I can answer for you.