High-risk deploys and slow iterations is not on you but on engineering management.
Not knowing who's responsible for reviewing your code is also not on you but on your manager, bad onboarding, bad documentation and general communication. Still you can check in the repo who's been working recently on adjacent work and reach out to them on slack/whatever and ask them.
I suggest to try and get small wins (like merging those PRs) as soon as possible and then pause and reconsider if this startup is for you. BTW, I don't see the "constant failure" you mention in the title anywhere, more like not being lucky with startups, which is normal since often they are shitshows.
Don't compare yourself to (selected, "successful") other people, compare yourself with the other possible selfs in different multiverses, how many of those for ex didn't take any risks and are in a worse position?
Also, this is more for maybe a professional therapist that for me but it looks to me that your definition of "failure" is unhealthy or too hard on yourself? sorry for the assumption but you are probably working on the area you want and like (technology) and being paid well for it. That puts you in the top 90% or whatever of people in <insert 1st world country> and 99.99% in the world (I know it's not consolation for feelings).
I have a therapist, but sometimes it can be difficult to talk through these things with someone who doesn't know the field or the ground truth.
My big stressor is that I have hit the jackpot, and where do I go from here? So many people I know have settled into a comfortable groove, but work is by far the biggest stressor in my life, it's ruining my health, and I don't really have a path out. Continually churning applying for new jobs or dropping out of tech altogether don't seem very appealing.
Similar to another comment - it sounds like you’ve made good money, you’ve landed tech jobs several times, and you’ve got good feedback from your peers - that is successful, you should take some time to take pride in what you have achieved so far.
I think there’s 2 things for you to think about. Firstly, comparing yourself to everyone else you will always find people who have done better in some area than you, that’s no failure on your part, that is the reality that every person exists in. It’s hard sometimes to appreciate yourself, I certainly have bouts of this.
Secondly, when you’re working in an organisation, you’re not solely responsible for making some project succeed, shipping some feature or whatever it is. If there are processes making progress very difficult, that’s not your fault. It’s easy to internally create all this pressure on yourself to meet your own standards, but sometimes you’re thrown into a situation where external factors out of your control prevent you from meeting what you yourself deem acceptable performance - that’s not on you. You can raise the issues that are blocking you, you can suggest ideas for improvements, but in a company, most of the time you cannot fix these things alone. I have found that my stress increases when I don’t understand what it is that is preventing me from performing, and when I put it all on myself to fix. Identifying the issues and absolving myself of the responsibility to fix all of them have been the best things I’ve done for my work stress levels.
Are they happy or are their parents happy at their “success”. Go watch some Frasier, it’s good for some perspective on success and happiness across career, family, personal baggage.
Not knowing who's responsible for reviewing your code is also not on you but on your manager, bad onboarding, bad documentation and general communication. Still you can check in the repo who's been working recently on adjacent work and reach out to them on slack/whatever and ask them.
I suggest to try and get small wins (like merging those PRs) as soon as possible and then pause and reconsider if this startup is for you. BTW, I don't see the "constant failure" you mention in the title anywhere, more like not being lucky with startups, which is normal since often they are shitshows.