You could inadvertently pass along proprietary information to a foreign government without even realizing it.
This holds true when a person is using non-Chinese communication or computing devices as well. Just because western economies are also democratic countries do not mean that those democratically elected governments or their intelligence agencies do not engage in the activities the Chinese national government and the Chinese companies are alleged with. Here, try this food for thought.
If you get hold of the book Permanent Record, its author mentioned one obvious but highly uncomfortable point: the internet, the computing and communication hardwares, and the softwares upon which the world runs at large are mostly US centric (whether developed in the US or by companies from the US), so it is natural for US govt and its agencies to make use of this monopoly for ends that may not necessarily be in public interest.
Let this be clear that this aggressive anti-China stance in technological matters is not precisely because of Chinese intrusive activities in civil and military affairs of the US and its nationals (this has been going on for a decade or more), but because China had the audacity and showed the capacity and the will to buy leading chipset and communication device
manufacturers of the US, and China -- a non-Western, non-democratic, non-NATO country -- further frustrated the US by beating it in developing, testing, and marketing the 5G (the next revolution in communications that would bring unimaginable amount of data -- currency for tech companies and billions of dollars to a 5G leader's economy). If there continues to be demand for Chinese 5G products (either by individual consumers for cellphones or by telecom operators for 5G communication and relevant equipments) in the US, its national security would continue to be undermined1 by China, so it is natural for the US to create this anti-China fear among its people and beyond.
Assuming the accusers are correct, does the use of Android One, as is done by some Xiaomi phones, reduce this risk, or is Android One irrelevant here?
- If you do not have access to the source code of the software you are using;
- If you cannot understand that source code in entirety;
- If you do not have access to the blueprint (or whatever that is called) of the hardware you are using (including the software that is part of the hardware);
- If you do not have the skills and the means to detect hardware vulnerabilities or backdoors;
than you cannot have absolute control over your device. You risk unwillingly giving away your private information to a party you may not even know. Everything than rests on trust (that you would not be harmed and the data not be collected involuntarily or misused) and the mitigating measures that you can undertake within the flexibility provided by the software and the hardware.
At last, if you want to stick with some western technological products, do it, but know that you are trusting one potential adversary with another. It is all the same if you are not from the western world.
1: FCC to vote to bar Huawei, ZTE from government subsidy program, sources say