If you're worried about failure then work at a more established company with a lower risk profile. If you're going to work at a startup then don't worry so much about whether it will succeed or fail, but rather whether you enjoy working there, you like your team, you like what you're learning and that you're getting compensated reasonably well. Anyone on HN that thinks they can predict whether your startup will fail based on 6 sentences you wrote about it is just blowing hot air.
Just as an example, I've been running my company for close to 15 years now and almost everything people are saying in these comments about failure could easily apply to me, and yet my company still exists and is going strong. I only promote from within the company, I never hire external management and it's a principle I strongly value. Apparently that makes my company a failure.
I always make it clear to everyone I hire before they accept that our business is risky and our company can go bankrupt tomorrow without warning. I never pretend or exert any kind of false sense of confidence and on the contrary I'd rather people understand and appreciate the risky nature of this business. Apparently that makes my company a failure.
My company pivots all the time on stuff and we are always looking for new and interesting projects to work on. We've explored crypto lending, decentralized poker, VR, prediction markets, and a social dining platform, all of which have failed but were incredibly worthwhile experiences that everyone had a good time working on and learning from. Apparently that makes my company a failure.
My company is big on tooling, from formal verification methods, to custom tooling developed for our in-house UX/UI team to prototype complex financial interfaces and data visualizations, to highly sophisticated performance monitoring and alerting tools, we even developed our own functional reactive programming language. Apparently that makes my company a failure.
With that said, maybe my company is a failure and next week I'll be the one to find out... but it's been a great 15 years for me and everyone I work with, we all get paid well, we get a chance to work on things we like with people we respect and I wouldn't have had it any other way, failure or not.