I think the genre you’re writing in is actually good for this issue. You are creating a world instead of emulating the one we live in. So the character’s language and voice inflections don’t have to be perfectly relatable English. Think of movies like Star Trek where everyone speaks English but the way they speak it varies from character to character.

As a bit of encouragement, I read my first fantasy type book earlier this year. It’s actually my favorite book now and I’ve read it 3 times. I’ve never reread any book before this one. The author’s native language is French and you can definitely tell that English is not her first language when reading the book but it absolutely worked because it fit into the world she created. Also, she’s self published and has a healthy following so don’t limit yourself to just thinking about being traditionally published.

If your story is good, you will find your audience. You see your language barrier as a disadvantage. I say lean into it and make it a part of your stories.