While deities like Waukeen, Deneir, Gond, Siamorphe have tangentially close dogmas to your character's goals, I think there is a more obvious choice: [Moradin][1].

Dwarven history has many stories involving dwarves relentlessly carving out new domains and kingdoms, expanding their territories, shaping the "wild" ore into tools and weapons, and turning formless rock into grand halls and underground cities. The dwarven pantheon overall represents many facets of this dwarven spirit, and above all, **Moradin, All-Father**, whose portfolio covers creation, smithing, metalcraft and stonework. According to the 3.5e *Faiths and Pantheons*, part of his dogma even goes like (emphasis mine):

> Advance the dwarven race in all areas of life. Innovate with new processes and skills. **Found new kingdoms and clan lands**, defending the existing ones from all threats.

It is not hard to imagine that the dwarves see themselves as bringing order to the uncivilised underdark. They will also see their human neighbors, or other trade partners as disorganized and unable to form lasting civilizations like they do. Your character might have decided to dedicate his life to bringing that civilized mindset to others by living amongst them and shaping the surface world along the time-honoured dwarven traditions.

Finally, Moradin is LG in alignment, while you stated that your character is LN. Your interpretation of Moradin's faith could actually fit this alignment difference, as you are trying to impose the "lawful" side of dwarven culture to others who are not necessarily asking for it.


  [1]: https://forgottenrealms.fandom.com/wiki/Moradin