> He seems to provide ample detailed western sources to back up his claims in every video

Does he? The only sources seem to be a CNSpaceflight tweet from last november of a promo animation from the missile company, and a South China Morning Post article that is just quoting commentators on Chinese state TV talking about the the possible capabilities of the missiles.

The other sources (someone else's substack that's sourced from a December article[1] from The Independent, and two articles on "interestingengineering") all just quote the same animation and commentators.

[1] https://www.the-independent.com/asia/china/china-hypersonic-...