They probably had a redistribution of free-tier and paid-tier usage in the last year-ish.

Just backseat gaming but a lot of those issues could probably be solved if they'd (temporarly) reduce the free tier. I'd say simply dropping Actions from it would reduce the load by a lot because then most vibe coders wouldn't bother integrating a CI/CD and either just use local pre-commit scripts or stop using those entirely. Not using a CI also drops the requirement for using PRs on solo-dev projects so they might also reduce load there.