The MNDAA is a close ally of the KIA as both are members of the Northern Alliance, and all the Northern Alliance members saw their relations with China tank after Chinese brokered talks with the Tatmadaw failed [0] last December.
As a result of that failure, all the Northern Alliance members began trying to pivot to other states or in the case of the MNDAA faced the brunt of the Chinese crackdown.
All of that postdates the MNDAA crackdown on scam centers, during which relations with China were excellent. It seems like after Operation 1027, the junta got the message and started handing over their own allies in the scam industry https://www.irrawaddy.com/news/burma/myanmar-junta-transfers... at which point China didn't have much reason to continue supporting anti-junta forces in their offensive and preferred freezing the frontline with a ceasefire instead.
Maybe the reduction of Chinese support encouraged the Kachin Independence Army to seek cooperation with India, but you seemed to be claiming that causality was in the opposite direction (while also misidentifying who was running the scam centers), which I think is clearly contradicted by the timeline of events.
As a result of that failure, all the Northern Alliance members began trying to pivot to other states or in the case of the MNDAA faced the brunt of the Chinese crackdown.
[0] - https://www.bnionline.net/en/news/juntamndaa-peace-talks-doo...