Backdoors with System level permissions
The problem with many of these cheap Androids is that they have backdoors which allow apps to be installed remotely with SYSTEM level permissions:
https://wuffs.org/blog/digitime-tech-fota-backdoors
And TCL/Alcatel, which can be found everywhere, like at your grocer, Walmart or drug store, has been found to be behind most of the malicious spyware apps found in the wild and on the Google Play store with ties to the Chinese State.
https://www.gadgetguy.com.au/tcl-and-alcatel-direct-links-to-massive-spyware-operation/
(But then the US has Google and Facebook so....)