Also cheap cameras at a higher resolution perform awful at night.
A good brand of camera will give a specification sheet.
For 4k (8MP), you would want near 1/1.2" cmos or larger... not a tiny 1/3" or 1/2.5" cmos sensor.
In Reolink's video you can see how the person 'ghosts' into the background at points.
https://www.youtube.com/watch?v=Y6Oxhxk8lxM
Ghosting happens with a cameras exposure is too long for the amount of movement. A typical reason for a CCTV camera to have a long exposure is because the imaging sensor cannot capture enough light to capture a decent image.
You can help reduce motion blur by adding external IR flood lights, but that adds extra power consumption.