Ask HN: What should an entrepreneurial CS student focus on this summer?

Wrapping up finals next week and want to maximize learning + career growth. In the process of sunsetting my first startup because wasn't able to find PMF. I want to grow as an engineer and experience the inner workings of operations at an early- mid stage startup but my attempts of cold-outreach have failed. Any advice?

about me: https://ellispinsky.com/