Not any worse than cheap crap from any other country. zero attention is paid to security. Software is just quickly checked that if functions on some devises, not tested and no security.

If you fear that Chinese install backdoor's, don't. These devices don't have backdoor's because the front door is open. Country of origin does not matter. Shitty American or European IoT device with no security is just as easy for Chinese and Russians to exploit as Chinese.

Is the product comes with smartphone app, it's worthless and insecure after 1-2 years later even if it's from known brand like Philips or Google. They stop doing security updates soon after they stop selling the app. Philips Hue lights, Google Nest home automation, Sonos spakers, ... worthless crap now.