when would you quit your HF job for a side hustle?

I work at a pretty well-regarded quant fund and make like $500K a year. I do not enjoy it at all anymore but I do it mostly because it pays me money. 

On the side I've been starting a company because I feel very unfulfilled in my job. I work about 30 hours a week on this side gig which is a DTC online business, so I'm working 90 hours a week in total which is unsustainable at least for me. At some point, I have to choose because I'm just so tired most of the time.

So here's the question: how valuable / lucrative do you think that your side gig would have to be in enterprise value or maybe cash flow terms for you to quit? How would you make this decision? If you're like "omg this is risky" what would your 25th percentile or median in your valuation range need to be for it to make sense for you? Curious to hear all of the thoughts on this thread.