When you ask Facebook for your archive it's already pure HTML. All you need to do is to censor it somewhat (if appropriate, e.g. remove private messages) and host it somewhere with access control.
That must be just a tiny bit of the entire data set they have about you. Tracking from all pages containing like button, all characters entered into chat, including those typed but deleted or not sent otherwise. I wonder how does it match against GDPR request.
Quite a bit. You'd have to do a subject access request to get closer to the truth.
You also need to remove the Facebook tracking pixels they have embedded in it.
For a moment I was briefly surprised, but then I remembered the company in question. No way that was accidental.
I've checked my own archive and they haven't embedded any tracking pixels. Don't spread nonsense.