Is it possible to update parent and nested (assoc) entity via one call in Repo?

Is there any way to perform update in Repo simultaneosly on parent and nested entity?

When you have has_one relation like in docs
create operation for User + Avatar works this way

 def create_with_avatar(data)

is there a way to do update in similar way?
because calling

  def update_avatar(user, data)
    assoc(:avatar, user).update(data)

would update only Avatar, but User is not updated (even if you provide correct nested Hash as data input like {username: "Yevhen", bio: "Cool", avatar: { url: "yevhen.jpg" }}).

Another question - is it possible to do somehow via raw ROM access (changeset or command)?