> I have tried a couple on this exact blog post, and QuillBot, for example, gave me 0% AI detected on it.

Don't use Quillbot; not sure why, but their model is reluctant to classify anything as AI generated. I ran into this when proof-reading a students Phd - ChatGPT, Gemini, CLaude (and others) all agreed it was AI generated, but Quillbot said it wasn't.