I’ll look into exporting guys thanks for your insights! There is definitely a way to do it, the owner of https://www.elitefourum.com/ moved from proboards to discourse and moved all their accounts/posts with it. I reached out to the owner but he had help doing it so he wasn’t entirely sure but I’ll see if I can find out more.
It is probably as you say @piffy very difficult, very closed of platform to get things out of. I’ll do some digging and feed back if I find out anything.