I did this recently at the company I work at. Someone suggested GitBook, I 'Vibe coded' an internal docs website in under and hour. Does what we need, looks good. Unless the app has a large community/network and is just a SaaS with some offering, it'll be very easy to replace it.
It's interesting, because a few years ago I would have put this strictly under the "not invented here" fallacy, where we'd now be stuck maintaining another project for the foreseeable future. I used to press pretty hard to avoid it.
Now I wonder if the maintenance cost for this type of internal system has gone down to a level where that is no longer an issue.