+1 to Brian on AIAs. That's Meta's approved route for putting a whole inventory in front of buyers, with the catch that they're paid ads rather than free listings.
One correction to my post above: I lumped our tool in with ones that post for you, and it doesn't. The GARAGEBIRDS Posting Assistant lays out the listing from the car's record in the DMS (details and asking price) and downloads the photos you pick; the rep pastes it into Facebook's own form from their own login. Tools that fill in and submit the form for you are a different thing. Meta's terms don't allow accessing Facebook by automated means without their permission, so those carry account risk at any pace.