Depending on how clothes/body meshes were implemented in Cyberpunk, this issue (not a bug/glitch, but clearly an oversight) may never be fixable. Even when equipping something that does not cover the torso, the game always switch to 'default' breast size. (I can provide a picture as an example, but I'm not going to post it here, since it would be NSFW).
It is as if breasts other than 'default' size are treated by the engine as separate meshes, sort of clothes, that are automatically equipped when nothing is covering the torso.
If you pay attention, also hairstyles are modeled around clothes: long hair do not fall on shoulders (as they should, if they were properly animated) but leave a gap around the neck and shoulders, to take into account the space occupied by clothes.
It is as if breasts other than 'default' size are treated by the engine as separate meshes, sort of clothes, that are automatically equipped when nothing is covering the torso.
If you pay attention, also hairstyles are modeled around clothes: long hair do not fall on shoulders (as they should, if they were properly animated) but leave a gap around the neck and shoulders, to take into account the space occupied by clothes.