When mashing prefixes onto words in a way which is unfamiliar, it's usually customary to use a hyphen. E.g. "post-fact[0]" instead of "postfact". Strangely, to me, the former seems to imply that "post-" is a prefix while the latter seems to be a fact involving postal mail.

[0] https://granta.com/why-were-post-fact/