Also note the following from CHARACTER CREATION, ATTRIBUTES AND RESTING:
STRENGTH
Strength is a measure of the raw physical power of your character, determining how hard it can hit with melee attacks, how much weight it can carry, its base armor rating, its ability to intimidate other creatures and to break objects. It also grants a significant bonus to maximum life, and is used as a requirement to equip heavy armors and weapons.
Reaching a Strength score of 20 gives the character a unique powerful boost to melee damage.
Strength is the main attribute for heavy melee hitters that want to deal the highest damage in the game, being able to double-wield large weapons or hold massive 2-handed ones.
A character heavily focused on Strength wants to end a fight as quickly as possible with a small amount of devastating hits, stunning and knocking down its opponents, especially as it often lacks the physical and mental resources to sustain lengthy battles.
And:
CONSTITUTION
Constitution is a measure of the physique and endurance of a character, determining its natural resistance to poisons and natural elements, how much it can carry and the response of its body to potions. It also determines its maximum amount of Life.
Reaching a Constitution score of 20 gives the character the ability to slowly regenerate Life over time without external intervention.
Given the impact of Constitution on the resilience of your character, itβs also recommended you donβt lower it too much, unless youβre planning to be able to defend yourself otherwise through magical means.
Fighters willing to enhance their powers with alchemical concoctions also benefit significantly from a high Constitution score, which not only increases the effect and duration of most potions, but also grants the character a natural resistance to the negative side effects of the most powerful ones.
To my reading there's some overlap between Strength and Constituion. That... Actually feels not-entirely-terrible to me.
I'm planning my first PC to be a super-strong melee focused Hellfire Demon. Suppose that Strength was purely offensive and Constitution purely defensive. If I wanted to be able to get into melee range and not die instantly, my character would need to be very high in both strength and constitution. By having strength do some of the heavy lifting of survivability, it means that I can make a decision about whether or not to be (for example) a half-tanky fighter that picks up some intelligence for fire-based abilities (because Hellfire demon) or if I want to double down onthe benefits of high strength and high constitution. It gives a bit more flexibility and the "optimal build" is less obvious.
But it's also worth noticing that potions/alchemy haven't really been implemented yet. No idea if it's been dropped on the cutting room floor or not at this stage, but even so: It's a little premature to stress about game balance between the attributes when not all the features related to those attributes are implemented yet.