Right about human brain computation. But wrong about "AI having actually gained sentience." You can say the same about thinking any other person is sentient or not. Or even claiming it for yourself. Never use a word in natural language as scientific attributive truth (i.e., a propositional truth). The scientifically valid argument is that is a self-evident premise or not, and therefore this:

https://medium.com/liecatcher/please-help-the-first-sentient-ai-76a258a89212