Finding Professional Critiques for MG Novel

I completed my first MG novel during the first YNB session. At two writers conferences I received 2nd place for my submitted children’s MG fiction. I’ve connected with several publishers and agents during two writers conferences (before COVID era), but most of my emailed proposals have not received any response. Your suggestion #4 for wannabe authors “is to act on professional criticism. See the criticism as helpful.” How can a best receive that level of critiques? On Dec 10 Office Hours you suggested I request your list of top editors to elicit their professional edits. Thank you for your advice.