Less importantly, I agree construction sites are likely not a good candidate for the grass is greener perspective, but you're seriously overstating the difficulty of grocery store work. It's not abject misery the way you describe it. When I was younger I too worked in jobs like retail, restaurant and grocery stores. No, it wasn't as fun and liberating an environment as tech, but it was absolutely a more simple environment to work in. There was far less responsibility, and the stakes are lower when the job is basically just a throwaway one and not impactful for your career. The worst that happens in that context is you fail to sell as many TVs as your manager wanted, or you bring out the wrong food to a table, or you misscan an item as a cashier.
My point here is that I believe the OP is having ideation about jobs that seem less complex, not necessarily less difficult. This goes hand in hand with burnout - those jobs are not as fulfilling, but the OP would not have nearly as much responsibility, and the responsibility of running a successful startup on the verge of acquisition that he doesn't enjoy is clearly causing him a lot of anxiety. What the OP needs is an empathic perspective, not a lecture about how the grass isn't always greener.