honestly there's no 'right' way to go about expanding your english vocabulary. your language is already very sophisticated and i respect that as someone who is also interested in learning and writing in foreign languages. just surround yourself with english works, books, poems, which is easy to do in this server, and eventually you will find that more words come to mind when you write. there is nothing to fight, rather it is something to embrace, because the english language is beautiful and colourful and full of extraordinary words.
another thing i'd suggest is going into a thesaurus (such as this one -> https://www.wordhippo.com/ you can find definitions, synonyms, antonyms, rhymes and sooo much more its amazing) and when you're stuck on finding a better word but you know something similar, look it up and you'll be surprised at what you can find. even as a native english speaker i use it a lot if my writing becomes too repetetive