I don't think it's the lack of trying that is doing you in, so much as it is a linear approach to entrepreneurship like what they will teach in business 101 classes: you are going through the motions without having the underpinning philosophy to animate them usefully.
A key part of this puzzle is knowing what you want to focus your mind's effort on: product design, coding problems, sales, etc. When you actually meet a market, you aren't just doing whatever you want and they buy it: you are engineering the specific thing that they actually buy, whether it's stereotypical "service with a smile" or "value for money" or "niche high end for discerning tastes". And advice about finding and optimizing performance metrics is exactly what this accomplishes. You have to consciously decide which metrics you want to optimize and throw all your leverage around their improvement, which tends to also throw you outside your comfort zone.
If you don't want to do that kind of sales-and-profits hustling, you're being an entrepreneur in a more speculative, "build it and they will come" sense, which has a much lower hit rate. But that doesn't mean you can't do it at all: you still have to decide on metrics for success, you just aren't using the surface ones now. It is in avoiding any kind of deliberate improvement that you trail off into having a non-functional business, and there are plenty of companies around that are alive, have employees and turn profits, but are in a zombified state, not really showing ambition - and that's definitely not entrepreneurship.
For example: you are in the business of manufacturing and selling crowbars. You decide that you will sell "the world's strongest crowbar". OK, now you have goals that produce a lot of activity: how strong are the existing crowbars on the market? What tests should you use to determine strength? Which materials and manufacturing methods will make your product stronger? What marketing materials will demonstrate the results most effectively?
At the end of that work, you may discover that there is no market for your crowbar, but there are opportunities for adapting the process to rebar instead.
When companies grow really big, the entrepreneurial process turns to one of creating a "machinery of people", vs proving that the market for employing those people exists. It's a different skillset, and is utilized only occasionally, when the stars are right and you happen to have a business that can scale. But it's still ultimately about setting the metrics that are right for that business at that moment.
If you aren't involved with fitness/sports/athletics, it's worth doing so just to get a taste of what focusing on performance and growth mindset day after day will do.