everybody also “knows” that the Facebook app listens to you
As for China - THIS the bog-standard procedure for any tech-related company when an employee has to travel to China. Give them a burner phone and laptop, zero company data on them, zero access to critical company data, after they return, just throw the gear away.
I honestly don't now what other proof would you need, when we know them spying on regular people has been happening for decades.