A Plague Tale: Requiem

It's Impossible to max all skills in one playthrough, what you have to do is start a newgame+ after you finish the game once, which let's you start over with all your skills and upgrades preserved, allowing you to max the rest of the skills your are missing.

You get experience in to a skill at the end off sections (not chapters) based on how you dealt with them.
If you kill less that 1/3 of enemies in a section you get experience in Prudence skill
If you kill between 1/3 and 2/3 of enemies in a section you get experience in Opportunism.
If you kill more that 2/3 of enemies in a section you get experience in Aggression