It sounds like you’ve maybe seen your resume in front of you and you’re reflecting on how it didn’t go the way you’d hoped, rather than the value in it.
Talk to a career coach who can help you write it from the perspective of focusing on your wins.
I don’t know you or your background but I doubt the story of your career is “I did a startup and it failed and I should’ve seen that coming and now I’m lacking confidence”.
Get the resume rewritten:
- Job functions. - Tech/skills learned. - Explanation of how eager you are for the next challenge.
Buddy, if you’re old in your 30’s then I’m ancient and I refuse to accept that. If you went to grad school then you’re probably at most 15 years out of school. That’s means you still have two thirds of a typical working life ahead of you. More if you’re lucky.
Make a plan and get yourself back out there.
By the way, I’d absolutely hire a late career switcher, because you’ve likely got more responsibilities than someone straight out of college. This might sound counter-intuitive (you can’t be easily exploited with 60 hour work weeks the way a starry-eyed grad can), but you also likely can’t afford to waste anyone’s time.