Appreciate the dialog, brother.

...is qualitatively excellent work solely achievable by Christians? (I don't mean _morally_ excellent--that is obvious, I mean work that is excellent _within its own discipline_.)

The 'dominion mandate' was given to Adam as a specification of the Covenant of Works, which he failed. Where he failed, Christ, the Last Adam, succeeded: "All authority in heaven and on the earth is given unto me." Whatever 'echo' of that mandate remains, it remains in a modified, provisional sense--and is non-redemptive. See Irons, "[Meredith Kline's View of the Cultural Mandate](https://www.upper-register.com/papers/kline-cultural-mandate.pdf)"

At no point are we, as Christians, placed back in the 'garden' and/or given some kind of renewed 'dominion mandate' in the sense it was given to either the First or the Last Adam. Christ's work is completed and it is sufficient. Our subsequent 'mandate' is to preach the gospel to all nations, making disciples, baptizing them, etc. Again, we are _pilgrims_ - in the world not of the world precisely because we are of the (inaugurated) kingdom but not yet in it (in its consummated state).