Serious guidance required, please.

Nope, Contrast AF is more accurate than Phase AF. It's more accurate becuase it uses the same focal plane as the actual image, the main sensor.

Phase AF relies upon the Phase AF sensor ( located in the bottom of the camera ) being at the exact optical focal point as the main sensor is. This isn't always the case and can change between lenses hence the need for AF tweaking parameters for each lens.

While being more accurate, Contrast AF is slower because it can't tell whether the lens is initially front or back focussing like Phase AF can. This means it has to make more guesses

If your chosen scene doesn't need speedy AF and you're shooting with a wide aperture then choose contrast AF