I can't say this is a 'happy marriage ' !
That's not how that myths works here. You have to find the part of reality the different cultural myths are the poetry that pre-scientific people used to map reality.
The Dragon of the West , in the Christian tradition is a symbol of primordial chaos like the Egyptian Apep (also spelled Apophis) and maps almost exactly onto the Leviathan/Tiamat/Satan symbolic pattern.
It / he (?) is eternal enemy of Ra, the sun god, and the thing the Solar Hero slays. The ancient Egyptian called this Isfet - chaos, disorder, falsehood, destruction. We might throw in mental illness here, so the Dragon becomes entropy, disorder, chaos, de-coherence , irrationality, falling apart, hysteria, madness, losing oneself. The illness is the issue, not the symbols.
But in Chinese Taoism, the dragon is the opposite, and is the symbol of heaven's order itself - that brings rain, that winds through the clouds in the pattern of the Tao, that the emperor claims as his symbol. All fine. They are allowed their own symbolic language in their own culture.
That said, are some some destructive dragons in Chinese mythology , and Western myth occasionally has wise or neutral dragon, but the main archetypal function is the one above.