First of all thanks for the comments @CodeMage and @WhatMightHaveBeen
@CodeMage
Could you suggest a modder? If it is not possible I will understand 
@WhatMightHaveBeen
I would like to discuss a little more about your formula (even if based on a few tests). It consists of:
weap dmg x (multiplier x (1+ rating% of leveling)) = dmg output
So we have:
x * (y * (1 + z)) = k
Where:
x - weap damage
y - thrall multiplier
z - rating% of leveling
k - final damage
Could you explain a little more about Z?
I will also follow the video from @Wak4863 (Thrall Strength and Damage check my math Conan Exiles 2020 - YouTube) treated in this post
