If a system’s rules are mostly for combat, and making a character mostly revolved around combat, then the reason people play it is probably for combat.

The idea of “the fruitful void” does exist, but I feel it exists more for systems that have fewer rules overall, or systems that are “loose” with all aspects, not games that have hundreds of rules in one area, and ignore the others. Games like Cities Without Number (which is am disappointed that the group Worlds Beyond Number isn’t using Worlds Without Number) have been great for getting players to think more about non-combat actions.
Choose a skill, choose an attribute, explain why those two, and roll if the GM agrees. Simple, leaves room for creativity, let’s players use their characters in interesting ways that still make sense.
Charisma and stealth because your character is “acting like they belong”? Go ahead, it makes sense. It also might have a different effect than another character trying Dexterity+Stealth.