Mediabiasfactcheck is not exactly unbiased themselves.

They're self-contradictory in their own assessment here. They find no failed fact checks, yet their accuracy is rated as "High", not "Very high". No motivation is provided for this. They also state RFA lists sources, but most articles on North-Korea especially only cite "Residents in the country", thus not providing anything verifiable. It's also why most major news outlets don't use RFA as a source, their stories are not verifiable. It's mostly sensationalist tabloids like The Sun in this instance that uses them as a source.

Additionally, Wikipedia does mention some failed fact checks, especially concerning anti-vaccine misinformation. See the article here: https://en.m.wikipedia.org/wiki/Radio_Free_Asia under Controversies.

RFA is not a particularly credible source for this reason. It's basically impossible to prove many of their claims, so scepticism is warranted.

This of course doesn't detract from the fact that NK is ruled by a nutcase dictator who brutally oppresses his people. But we don't have to necessarily trust a story with as much credibility as some fanfiction here. This story could well be true, but I don't want to assume that this is fact based on the nonexistent sourcing.