How to update JSON field in SQLAlchemy

Question

I have a settings model in sqlalchemy with flask

class Settings(Base):
    __tablename__ = 'setting'
    settings = db.Column(db.JSON(), nullable=False, default={'connections': []})

    def serializable(self):
        return {'settings': self.settings}

    def __repr__(self):
        return f'<Settings for {self.project} id: {self.id}>'

When I try to update settings field in the Settings table it just does not stick.

@settingsBP.route('/delete/<connection_name>', methods=['DELETE'])
def delete(connection_name):
    settings = Settings.query.first()
    settings_copy = settings.settings

    for i, v in enumerate(settings_copy['connections']):
        if v['database'] == connection_name:
          del settings_copy['connections'][i]
          break

    settings.settings = settings_copy
    db.session.commit()
    return jsonify(settings_copy)

If I print settings_copy it prints correctly. But the settings.settings isn't saving any of the changes. I tried modifying the settings.settings directly but that did not work.