My guess is that the problems stem from the sensor used, not the software.
If a sensor is a low-cost 8MP CMOS, even the f2.0 will not save it from taking grainy/blurry pictures indoors or at evening.
Getting technical, the pixel size of 1.12 μm in Nokia 3 is not too promising either.
F-values don't matter much on phones with lenses the size of small beads.
This is a value phone with value specs and a value camera.
Software tweaking would in all likelihood improve performance only marginally.
I kind of found the reason. Its not just an old cheap sensor. Its a goddamn Samsung camera unit designed for front cameras put on the back. If I wanted a cheapo samsung sensor I would have bought a cheapo samsung phone. It does not focus because it cannot. Feeling cheated and going to switch asap. Probably the honor 6x with an actual Sony Sensor. This was a heartbreak.