You post to a location you control, then post the link to that to other sites.

That way you own and control the content.

There’s a reason why Meta and Twitter hate external links, it takes people out of their feed

Obligatory XKCD: https://xkcd.com/386/ 😀

But more seriously: I do frequent shitty FB forums where newbies ask the same question over and over again. I can just quickly copy-paste my longish and sourced response every time. I’m pretty close to just setting up an Alfred/TextExpand macro for the most common ones 😀

(On a proper forum we could just point them to a FAQ thread, but Meta makes is intentionally hard because ✨engagement✨)