When you mentioned projects where you did well, what did your boss say?

Honestly I’d not bother with HR. It was the same in your previous job, if you didn’t like something coming from a boss you went to HR. It never worked. Unless it’s a formal complaint about discrimination and harassment (hard to prove) HR cannot do anything. They aren’t above your boss, they don’t know what’s right or wrong in your review. For a meeting with your CEO prepare some stuff to show that you are improving. Always collect evidence and documentation and have it ready for a review

I doubt they just fire people after they gave them pointers to improve. They have to give you time to improve.