Writing tips: Can you salvage what you've written if the book just isn't working?

I recently completed the first draft of 2 books, part of a series that were going to be in the post-apocalyptic genre. It was going to be set in Australia and it was going to be great. Everyone I spoke to loved the idea of a book set in Outback Australia. Including me. And yet, in March 2020, after I had the storyline, the characters, the events, the twists, and all the action for 2 books completed, and just as I was about to start book 3, I realized something: I hated this story. That's not a good position to find oneself. After over a year of writing these two books, I hated the books and didn't want them released. I was ready to call this a year of lost writing. Instead, I set this series aside and returned to writing book 2 in the Earth Quarantined series, which I had set aside to write those post-apocalyptic series. And I remembered how much I loved writing in my futuristic world that as soon as I finished the first draft of Earth Arrested , I came up with an idea on