The story ended. All that remains is the art.
Canon Ending? I think the "Hidden Lover Slut Ending" would be the Canon Ending in case I ever decided to continue this series, which I don't at this moment. There are many other projects after all that I plan to pursue. So it is best for you to assume that the game ended for now. Chances are there won't be a Sequel, unless many Patreons wish for it in the future.