A changelings change apearance states

You also can't appear as a creature of a different size than you, and your basic shape stays the same; if you’re bipedal, you can’t use this trait to become quadrupedal, for instance.

But seeing that with a druids wild shape can change you into a creature that is quadrupedal and a differernt size as yourself, does this mean that after that you can change into another quadrupedal creature of that same size?

lets say you are a normal 2 legged walking medium changeling and you wild shape into a 4 legged walking large saber-toothed tiger. does that mean that you can use the change apearance feature of the changeling to change into another 4 legged walking large creature like a dire wolf? and can you use this feature to change apearance into a creature outside of the possible druid wild shapes? for example a creature with a higher CR?