The problem is your advisor sent you on an unknown journey. A Ph.D. thesis isn't a postdoc project. You needed guidance on the journey and course correction but didn't receive any.
I also went on an unknown journey but the difference was I had a weekly meeting with my advisor and we talked and tried to find a solution. I wrote a few pages in my thesis explaining all our failed approaches. But the difference was my advisor helped me. He saw me working on a dead-end solution and he said it doesn't work to find a different solution. After 5 or 6 attempts, we found a solution.
PhD advisor is not necessary someone who knows the topic. It's someone who teaches you the research and guides you.
I also went on an unknown journey but the difference was I had a weekly meeting with my advisor and we talked and tried to find a solution. I wrote a few pages in my thesis explaining all our failed approaches. But the difference was my advisor helped me. He saw me working on a dead-end solution and he said it doesn't work to find a different solution. After 5 or 6 attempts, we found a solution.
PhD advisor is not necessary someone who knows the topic. It's someone who teaches you the research and guides you.
Don't give up.