First steps for a SE to getting involved into AI/LLM?

I've been fired recently and while I look for a new job, I would like to start learning about the new LLM/AI wave, and specially, how to work with them from a software engineer standpoint. My only experience is to use OpenAI API (prompt -> output), but I see a lot of startups everyday mentioning new models, new features, etc., and I'd love to learn that (not only curiosity, but also FOMO, especially now that I need to sell myself in the job market).

Is there any good tutorial / guide / tool? I tried Google but it goes from super simple (OpenAI API) to something super complex, and I am looking for something more pragmatic.