It's not limited to Chinese phones. It's happening with Samsung and Apple phones as well.
Currently this issue is widespread on all smartphone brands. Because almost all brands use Samsung's display. It seems a huge batch of Samsung displays made during COVID times had quality control issues. Hence it's affecting all brand smartphones.
Motorola uses LG's pOLED displays. Hence you'll see less such cases.
Now Apple is also in talks with LG to provide them with Displays for their upcoming smartphones. They are slowly bringing down their dependency on Samsung by also getting displays from LG and BOE.
Although
@hike bro's case seems purely due to the phone's age. It's a 6 year old phone. Right now only display is giving issues. Soon there will be issues with battery, cameras, speakers, network, and so on.