She's back to wearing clothes so tight you can see her Spanx line. My first thought is she's starting to take after her mother
When seeing the pictures the first time, I thought Sofia really has to get used to her 'new' / 'post becoming mother' body. Apparently she believes she can go for super- super- super tight again.
It's not a flattering dress on her imo, it's obvious she's crammed into a girdle of some sort. I think this sends a bad message to new mothers. It doesn't seem to me that she's embracing her new body shape, as you said. She's trying too hard to be hot, which is what she's always done. She's worried about all the wrong things, mainly body image. Typical.