There are no easy wins to these problems.
You can't both simultaneously allow adults to use explicit chatbots, and also block them from children, without requiring some form of identity verification.
The real problem is the lack of adopted robust standards by the government for age verification that don't require you to disclose your identity.
The technology to do kind of this already exists, it is called zero-knowledge proofing. it has existed for a decade and is widely deployed in other countries like Estonia.
Most countries are so incredibly far behind the 8 ball on this stuff and they let government and big tech to keep eating away at their freedoms instead of electing and bringing competent technologists into the government to solve the problem.