Here's the best strategy at this point. Talk to the VCs.
Thank them for sharing their opinions. They did a good thing that a lot of investors don't do: they gave you an actual rejection, rather than wasting your time with "we just need more information" and indefinite deferral. Knowing nothing about your situation, it still sounds like you ended up meeting some good-apple VCs. Reach out to them and ask if there are any open positions in their portfolio companies that might give you the skills to create a more viable business in the future.
Don't let your co-founders know that you're doing this. They probably see those VCs (for rejecting them) as an enemy. They are, of course, the opposite. They did a really good thing by pushing you away from a bad idea. Not everyone in that world has the courage to reject someone (as opposed to delaying indefinitely, which has the same effect but is less honest). You should reach out to them for general career advice and see what happens.
Regardless of whether the VCs help you, it's time to wrap up your startup. Do any documentation work that's needed, get your specific equity amounts in writing (founders will often get resentful and try to steal your equity if you don't, and you won't get much sympathy from the courts if it's just a verbal agreement; that means you fucked up). Try to leave on good terms so you can keep a good reference, but don't hold high expectations because usually a startup breakup causes one side or the other to burn the bridge outright.
Good luck! This is not an easy thing to do. When you leave as a founder, it feels like defeat-- it's not just changing jobs, but it feels like you're admitting that you don't belong in charge. You can't let that get to you. You made some bad choices-- it sounds like your co-founders were not made of the right stuff-- but you've learned a lot, and now it's time to recover.
If you can get consulting work or a really good salary job (i.e. one that will improve your career, not waste your time) then that is the best way to move forward. I wouldn't recommend trying another startup for a few years. Startup failure is really hard to recover from; you need time and a low-stress environment.