How is the Damage Roll Multiplier for Kinetic Knights Calculated in Pathfinder Kingmaker?

For example, some of my characters have damage rolls of 1d6+5, and my character (a Kinetic knight using a kinetic blade) has a damage roll of 4d6+7.

I am aware that 4d6+7 means that I roll my dice four times, add the result, and add it to 7, giving me an attack value anywhere between 11 (4+7) to 31 (24+7). I am also aware that some weapons have fixed damage roll multipliers (as shown on the Pathfinder Wiki).

However, I haven't found any sources explaining how exactly the damage multiplier is calculated for my kinetic knight's kinetic blade. I have seen other people with damage roll multipliers of 10 (10d6+1, for example). The game doesn't really explain, and I have been trawling forums and the in-game encyclopedia in search of the exact formula, but to no avail.

Thanks in advance for answering my question!