1, the book distribution channel really only cooperates with publishing houses; Your book is handled by a cultural company (publishing agency). You can ask cultural companies to help you promote it through their own distribution channels, at least on their own websites. They usually help you. If you want to enter the distribution channel, it must be a publishing house or a cultural company that will help you if you think your book has a market, otherwise it will be very difficult.
It's better to find a market than a publisher. After all, books are market-oriented and reader-oriented. Now that the book has been published, I personally suggest you go to some crowdfunding websites to gather readers through crowdfunding.