I’m ukrainian and for most of my life I’ve read tons of fanfiction and sometimes even real books in russian.
A bit cringe but eh whatever - I was born south (Kherson) and that means I’m bilingual by default, there were few people who actually didn’t know or at least understand ukrainian - a lot more (in the west) don’t know russian.

And not like there’s a ton of fanfic in ukrainian - although I’ve learned that 40mil people is 40mil people and the culture is way more diverse than I previously thought, there likely are hidden ukrainian fanfic gems.

Living in Kyiv, and I’ve been to far west a few times as well - nobody bats an eye at russian language (with rare understandable exceptions) - it is impressive how stupid an individual should be to believe some cringetastic propaganda claiming that russian language was ever oppressed here.
Like I get how after 2022 some people might be unhappy and I can easily switch to ukrainian, it’s just polite lol - but the most systemic oppression ever observed is the law they passed that cashiers are required to reply to you in ukrainian, and you can learn three phrases real quick if you somehow completely don’t know ukrainian while living in Ukraine.

Anyway, the point was, only around 2023 I finally bypassed the weird mental block that prevented me from reading English literature - at that point I’ve been fluent in English for years, watching YouTube and movies, using it at work etc - but my eyes hurt (metaphorically) from trying to read books in English.
So I got over this block and of course the world of English fanfic is significantly broader than russian - now I’m actually impressed that russian is as big as it is actually.

Note

Just looked up the Moon Reader statistic history - the first fic I’ve fully read in English was Intuition, starting at 13th of September, 2023