I had English classes in school for 10 years and some uni courses in English. I had to make an effort to write well there. Other internet forums like reddit might also be a good place to practice writing, basically any place that isn't full of runglish and memes based on wrong grammar.
Does writing well really matter to you, though?
In any case I recommend reading books in English. It's lower effort, can be fun because you can read about something that interests you and reading literature is best for developing a good vocabulary.
