none of those references suggest there is anything wrong with the official stats, but that was just a cursory browse from my side
The first three show evidence of prices going up faster than official inflation figures, and there is no shortage of similar articles, a cursory glance is all you need really.
The fourth link is more interesting, they're not claiming the official stats are BS, but they are questioning why the official method has not been altered or questioned that often and they propose an alternative approach.
if you say the official stats are BS, you have to provide alternative stats, that's how it works and besides you said it would be easy to do, you would think someone would have done it by now if it was that easy
If the government benefits when the real inflation is misrepresented as a lower figure, why would they change it?