Its a rather simple situation, they would never publish this if true, and wouldn't publish this if false. Period. Nothing to "ask for sources about". Simply choose which you belief or don't make a choice.

But please don't suggest lack of Chinese sources is a relevant data point.

This is a cheap argument because it builds on a false premise. Because there are also no impartial humans. It makes it sound like the onus is 100% on the media to always proof it's correctness which is a fallacy. You need several things

1) best intention from the media to be unbiased

2) minimum level of intelligence to spot bias and question the motivation by the reader

3) trust from the reader in the media that they're not willfully misled

4) trust from the media to the reader that they put things into the correct context within their own belief system

even one has (hypothetically) all of those, the audience will still be bitten by not sharing the same historic data and personal experience to put things into identical context as was available to when the info was produced. then there is the time-lag from when it gets written/published/read that distorts.