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They're basically one and the same given that one of DTI's factors is Income (speaking mathematically).
Higher income good, lower debt good, but the ratio between the two of them determines how much house you can afford. You gave your stats but also mentioned, or at least what I'm reading, "we're" which suggests a second borrower too.
If you're together on the purchase, both incomes count for DTI purposes, though so do both debts heh.