If thousands of deaths in China, a complete lockdown that hit the economy incredibly hard and perhaps more crucially, the total breakdown and potential reshaping of the global supply chain, which China has been benefitting from massively, is something that the Chinese gov wants to to achieve, then such conspiracy theories might hold water. I think it's plain to see how nonsensical they are.

Also, nobody made the US look bad but themselves. This is obvious if you compare COVID responses in countries like Germany with those in the US.