The South China Morning Post itself recently wrote on speculation that Beijing could try to challenge Tokyo’s control of Okinawa, given its history and proximity to Taiwan.[0]
[0] https://www.scmp.com/news/china/diplomacy/article/3333468/ch...
This is to counter the claim of the Japanese PM that Japan might join in the war if China goes for Taiwan.
About a decade ago, some Chinese propagandists were encouraging calling Okinawa the Ryukyu kingdom and trying to ferment an independence campaign. It didn’t get too far.