Contemplating leaving a successful startup [I will not promote]

I’m a cofounder and the CTO of a startup in a fairly niche B2B sector. We started 5 years ago, and have been bootstrapped this entire time. We’ve grown our customer list pretty effectively and have many leads in the works still. Problem is, I’m super burned out. For 5 years I’ve been putting in 60-70 hour weeks, and it’s really getting to me. To top it off, I feel that my salary is below what I could make as a standard software engineer with my experience. We’ve recently decided to do a proper VC raise, and had a mentorship meeting earlier today to get some guidance. I brought up that one of the things I’d like from the raising capital is to increase my salary, so that I’d be getting market rate. He basically laughed at that idea, and said that there is no respectable VC that would be willing to let a cofounder make market rate pay after only a Series A. So now I feel like I’m working twice the hours of a standard job and making half as much, which has gotten me pretty down. Of note, although we’ve grown our developer team and have 5 devs under me, I still manage the majority of the production workloads. Managing infrastructure, security, architecture, roadmap, etc.. (which is obviously all my responsibility as a CTO). But I want to say that, without any ego, I’m the most valuable asset in the company. To the point that the other cofounders have taken out a keyman insurance policy on me just incase anything happens to me. So now I’m really conflicted. If I leave I feel like the company won’t survive. But at the same time I’m tired of being overworked and underpaid. Lastly, if I do decide to leave I want to do it before any fundraising takes place, as the other thing the mentor has told me is that it’s common for the cofounders to revest half/all of their equity to show they are “all-in”. So if I want to not burn my equity I feel now is the best time to leave. The dead equity might be an issue for fundraising, but worst case they can buy me out maybe? Has anyone been in a similar situation? Any possible advice you can share to help me with this decision. It is five years of building something from scratch, I don’t want to make this decision without taking everything into consideration.