In short: go big or go home. I am assuming your problem is raising money. If not, discard this answer.
You probably should not restart but rethink instead, for, in this funding climate, your startup has likely been taught to pursue a cheap downstream optimization of the norm rather than a risky higher normalization of truth yearning to break the norm. The former is what the overwhelming subprime arbitrage of venture capital, supported by its reverberating pageantry of “innovation,” has promulgated for the last twenty years.
I say all that without knowing your specific idea and based solely on the statistical outcomes of said innovation arbitrage. As most venture investors operate on the principles of risk diversification and risk aversion filled to the brim with deal collusion, deal fragmentation, and deal syndication, forming an inherently subprime innovation arbitrage by definition unable to find outliers only systemically capable of attracting subprime ideas. Or in Einstein’s words: The theory determines what can be discovered.
The outcome of their arbitrage yielding a dense fog of false positives and false negatives, on the surface, appears the same. Yet, if attached to a higher-normalization of socioeconomic truth ready to break the norm, a false negative will and must be met with an overwhelming amount of rejection from subprime investors. Hence, while you deem your startup to be a failure for the inability to close funding (yet) may instead be the very premonition of your success.
Just like Elon Musk’s idea, which every major Silicon Valley venture investor tossed out as a false negative, now proving to be the most meaningful innovation Silicon Valley has produced to date.
Your process forward depends on the value of your idea and its ability to strengthen the evolution of humanity based on discoveries that are not yet the norm. Still, you have the fortitude to make them be.