I am wondering if is it possible to create a global score using multiple KPIs with different scales.
Example:
I would like to join all this KPIs in one score that could tell me what version is better. Is it possible? (I consider the 3 with the same weight in the score)
There is quite some theory on (credit) rating methods which provides a profound mathematical base for what you are after. You might start reading about score cards in general. An abundant way of combining different scores uses Logit.
The short answer to your question: There is no single best way to combine three KPIs, you have to try different formulas, and decide on one of the formulas based on some statistics tests in a validation step.