I've worked as the first sales leader at multiple startups, had my own, and now do consulting for early stage startups. This isn't a sales pitch, 98% of you wouldn't be a fit anyway.
I won't bury the lede...You have to stop spending all of your time building your product. And spend a lot more time on sales and marketing.
I keep seeing talented founders with a product background neglect sales and marketing.
You have to go out and talk to customers. You have to send cold emails, you have to pick up the phone, you have to get rejected, you have to hear people shit on your idea. You have to build up a rejection tolerance. Prospecting to fill the top of your funnel is going to be a major pain in the ass early on but you'll learn a lot and when it starts to work, you're going to create momentum for your startup which is key.
You have to create content, you have to spend time distributing the content, you need to leverage LinkedIn even if it's a cringefest because it works , you have to get eyeballs on what you're building.
Outbound sales and marketing increases your luck surface area. This is how good things happen.
If all you do is sit behind a keyboard and build, you're going to increase the chance of failure. Depending on your stage, you need to dedicate time each week to either talking to a ton of customers or selling+marketing. And as you sell you still need to talk to customers. As Justin Kan points out, you learn with experience that distribution is critical. You can build a great product but if nobody knows about it or you can't get prospects on a call, you might as well not build anything.
Customer conversations can turn into a better understanding of the problem you solve (improved product), relevant marketing content you can repurpose for a variety of channels, and more effective outbound messaging.
It's uncomfortable to do anything you're not confident in like selling and talking to customers but you'll learn. You'll get better, you'll create that precious startup momentum, and you'll put yourself in a better position to succeed.
Happy to answer any sales related questions you may have!