Ask HN: Tips for a back end/infra developer between jobs?

Hi there. I used to work as a backend/infra developer at a top company in bay area (in tech aspect IMO). I moved to a new place and am now waiting for work authorization.

I want to stay sharp and either learn or work on something. However, for backend stuffs I do not have access to a system to solve problems with, which is inconvenient. I am open to non-backend stuffs too. But I am not familiar enough with other areas to see what is worth working on.

Of course I could try to learn something new and work on a dummy project just for learning, but I hope there is a more exciting option.

Any tips will be appreciated.