That’s the thing, having kids is a unique experience just like not having kids is a unique experience. Being an individual is fundamentally a unique experience. Yet this whole conversation gets wrapped up in normative language like this which clearly expresses social preference for the former.
When I hear someone say that having children changed them in a profound way, I don’t hear anything other than “climbing a mountain is profound” or “laying on the couch all day is profound.” There is uniqueness and profound cumulative existence baked into to every heartbeat, but apparently a lot of people have trouble with this simple idea.