I've used OnePlus phones for the past 6 years as they have been really good quality and comparable spec to the new iPhones brought out at the time of purchase for half the price. Thankfully I didn't buy mine from China so I should be good.
Xiaomi, my partner has used one of them for the past year and by default that uploads all your photos to there own cloud service (had to disable that).
Personally I wouldn't be that worried, as if you have Google on your phone anyway they are probably gathering just as much data too I expect. People just need to use there common sense, if there is stuff they want private then don't put onto your phone unless in a locked folder etc.
They often like to make how that the Chinese are gathering all this data, but I bet they aren't the only ones doing it.