I want to improve my English-language writing because I want to become an English-language writer in 5 years. I want to improve my English-language writing because I want to become an English-language writer in 5 years.

English writing isn't wrong but this is a bit more formal

I worked as a journalist in China for 2 years and I have also written culture criticism essays for some media outlets. I worked as a journalist in China for 2 years and I have also written culture criticism essays for some media outlets.

Or 'publications'. 'media' by itself is a bit broad

I worked as a journalist in China for 2 years and I have also written cultureal criticism essays for some media. I worked as a journalist in China for 2 years and I have also written cultural criticism essays for some media.

I love the feeling of using a language carefully and navigating the details to make subtle differences. / distinctions. I love the feeling of using a language carefully and navigating the details to make subtle differences. / distinctions.

Here in an English-speaking country, I cannot use my writing skills and cultureal understanding to find a writing-related job. Here in an English-speaking country, I cannot use my writing skills and cultural understanding to find a writing-related job.

Here in an English-speaking country, I cannot use my writing skills and cultureal understanding to find a writing-related job. Here in an English-speaking country, I cannot use my writing skills and cultural understanding to find a writing-related job.

I took some weeks to find jobs, but this week I suddenly realized that what I really want to do is writinge nonfiction, as I did before. I took some weeks to find jobs, but this week I suddenly realized that what I really want to do is write nonfiction, as I did before.

Slight tense correction

I took some weeks to find (search for?) jobs, but this week I suddenly realized that what I really want to do is writing nonfiction, as I did before. I took some weeks to find (search for?) jobs, but this week I suddenly realized that what I really want to do is writing nonfiction, as I did before.

So now I want to practice my writing and listening English to make me qualified beingto be a writer here in Canada. So now I want to practice my writing and listening English to make me qualified to be a writer here in Canada.

As above

So now I want to practice my writing in and listening to English to make me qualified beingto be a writer here in Canada. So now I want to practice writing in and listening to English to make me qualified to be a writer here in Canada.

Why do I want to improve my writing EnglishEnglish writing? Why do I want to improve my English writing?

Or "writing in English"

Why do I want to improve my writing EnglishEnglish writing? Why do I want to improve my English writing?