Maybe this can help testing? Bleeding Heart - Unique Jade Amulet
Also, I knew there was a thread discussing exactly this, and I did manage to find it… It’s still open, and OP got some findings he shared there. I didn’t bother to recap on everything I missed since I last read it, but you should give it a look.
According to OP on that thread, armor-dot-mitigation is indeed capped.