Re on Huawei, I can provide a deeper insight. I've interviewed with them 10 years ago, and even for someone like me (Chinese descent, three generation removed, with full grasp of the language), I did not feel I could fit with some of their corporate culture.
I had friends who joined them at senior levels (directors). Mgmt teams from foreign countries are required to go to the Shenzhen HQ for on-boarding. For foreigners, it is the usual corporate spiel that you get at MNCs, and you knock off for sight seeing at the end of the day. For PRC citizens, there will be evening classes, conducted by the CCP. The content... well, you can guess (loyalty to Party and China stuff)
Does Huawei kit have spyware? It was my question to them. I think the answer is complicated. They (Huawei) are not stupid. They build very good devices and are affordable and being Chinese, they love making money more than politics. They are also aware of this perception and frankly, as an engineer, it is not easy to get away with such things on a large industrial scale without being detected. So yes, I am reasonable confident that they don't stick a rootkit into their ROM for most part. But what I am not confident is if the Party as them to do it, or asks them to provide confidential information of the clients, they will not say no. This, I think is what security agencies are worried about.
Re working there, even for us oversea born Chinese, we are subjected to double standards. No matter how hard we try to integrate, there's still some level of barrier at the social level. At the corporate level, there are subtle but material discrimination. Slightly better compensation for the same role, little or no need to justify for a more expensive hotel or business class during corperate travel etc.