1) To echo some of the other comments here, getting a regular routine will help you get into better habits. Good sleep, regular exercise, and limited social media etc will help with your mood.
2) The setbacks are situational, not dispositional. It really is a shit job market and you likely don't know how to properly signal yet (ie. sell yourself to others). And to make things even worse, brute force ATS grinding is now even less effective since everyone can now game the systems and generate a plausibly good-looking coherent resume using AI.
3) IMO, one mistake I see often is that students think jobs are the only way to gain experience. This is not true. You really have to be constantly learning new things on your own. Your university education is not enough. This means working on projects specifically for learning purposes. I'd suggest you alternate between learning-mode and applying-mode, where you spend 2-3 months just working on shipping a complete project, then focusing on applying to jobs for another 2-3 months, get feedback and rinse and repeat. You can use the learn-mode time to adapt to feedback. I think this will yield better results than applying over and over again hoping for different results.
Anyways, feel free to reach out. As others have said, you're beating yourself up too much. You'll figure it out and find a way through these setbacks. The important thing atm is not to spiral into a vicious cycle. I applaud you even airing this on HN, as it's much much better than sulking alone.
There are terms other than valuation which are very important (board rep, liquidity pref, etc). Have you talked about what are the must haves and deal breakers for you and your team?
IME, the bigger issue in the long run with this situation is that you, the founders, do not have a direct relationship with the investors. These investors will most likely be "his" investors, which positions him as a key intermediary. This will be a problem in the future when you need to manage them and must go through a middle man.
The CEO should ideally lead the pitch and an advisor can help with coaching, networking, and strategy (and be well compensated for it). I think any competent VC will want to see that at least one of the founders can do sales.