You do have inherent copyright whenever you post, but it puts the burden on you to prove damages (or how much financial harm you suffered from one LLMs piracy alone). Filing fees are $65 for online registration and they allow you to claim atty fees and statutory damages. Statutory damages can range between $700-$150k USD per LLM because you registered it.

So yes, set up some scripts, you can go back 90 days from when you file (you get a grace period). Also if you're publishing frequently to a blog, repo, or newsletter, you can save cost by filing each article under a group registration. Ping me if you need help.