There are so many native speakers who can’t spell well or don’t understand subject-verb agreement. So, I don’t think you need to worry about that demography. I grew up in Canada with two Japanese immigrant parents. I also can’t call myself a “real native English speaker (NES)”—as some NESs have also told me (basically I’m not white—their words). But the clarity and sophistication of your writing are what makes an article on Medium attractive to read for a wide audience. Just my opinion. Please keep writing as you do!