Sure, about as much as hardware from any other manufacturer. Maybe Fairphone might be more trustworthy than the rest because they care about the supply chain and are not that popular (hence they're less likely a target), but other than that, I don't think I'd trust any brand over another based on their country. They all get their parts from all over the planet and the software is also from all over the planet.
I'd rather look at their profit model, which in Xiaomi's case is not just selling phones: they bake advertisements into the OS and are open about that being part of their profit model. Which would be fair enough if everyone understood how technology works and where your data goes, but very few people really understand that. For now, you can opt out and/or root or flash your phone, but this kind of thing usually becomes mandatory once the majority of people got used to it and there won't be a big outcry. Turning it on mandatory affects everyone, but turning it on as opt-out gives the media little to talk about; then, when most people have left it turned on anyway, it's a much smaller change to make it mandatory.
