The inversion you're describing is striking — faith as *less* to carry, not more.
Tolkien built this into the bones of his mythology. Aragorn spends decades refusing the throne he was born to. That relinquishment of outcome is exactly what makes him capable of decisive action when it matters. The man who grabs for kingship is already compromised. The one who can take it or leave it is the one you actually want in charge.
The Dostoevsky point is the hard one. Secular commitments can absolutely reorient a life — but they do seem to need constant re-earning. The question of *why this commitment, why this justice, why now* never fully quiets. A transcendent anchor doesn't argue back.