Idea replies — I’m a ghostwriter with a published YA novel and a dystopian sci-fi idea I can’t crack alone

What if you treated your own novel as a client project? Write yourself a proper brief, deadline and outline, then hire a developmental editor for just a few sessions to hold you accountable. You clearly know how to finish books when someone else is expecting them. Maybe the missing ingredient isn't another writer, but someone playing the role of your client.