One problem could be that they are even less expensive than you know.
Banggood sells what seems to be the same strip for $2.59
These LED’s in strip lights are configured in a series - parallel configuration. Are all of the LED’s that start to flicker next to each other? If they are, you could simply snip out the bad section and either replace it with a section from you other strip, or eliminate it altogether
The flickering starts near every 18th or so LED, one or two. As time passes the amount of LEDs in sequence grow, that go out. This begins from where the roll/strip is attached to the plug connector, through the entire roll. So basically I cut out the bad, and replaced the entire strip for the sake of splicing short sections with connectors and added expense. I will not be wasting my time buying this type of novelty again.