I’d reach out to your professors about your misgivings about your research. Make it clear that you’re looking to complete the thing asap and need guidance.
Forget the outside stuff. Relationships can wait until you’re done. Feeling like a failure or success is almost a worthless concern as you’re clearly nearly done with a huge life goal. A life goal that will change the context of your life ever after. Much more than any marriage could even. Marriages are fundamentally just a societal complication of a relationship - complete with dubious legal consequences and a not a sure thing that can end. (Plus if someone is bailing on you when you’re finishing a degree they definitely weren’t going to be there for you in actually troubling times - like an illness or your house burning down.) But a degree is a hurdle you surpass once and get to wave the success of forever after. (Just don’t be a jerk about it, side point.)
Know that on the other side of your phd is a huge weight off your shoulders regardless of failure or successful defense. This time of strife will end when the phd. Freedom is soon.
You’re looking at a time where the job market remains strongly favorable. I graduated into the Great Recession and would have benefited greatly from this market, high interest rates and other things be damned. The future is still bright - just got to get past this last bit.