They've got a billion-strong userbase and yet the Android app still dumped literally every attachment I received into my camera roll until I manually added '.nomedia' files in the right places.
And, oh man, the API for businesses is a Kafkaesque nightmare. Maybe it was good before it got Zucked, but I had to fight with their support for over a week to get an automated ban-hammer overturned... only for it to get auto-banned again two days later. We hadn't even deployed the damn thing yet!
There's a global setting for this: media visibility: off.
Then you can enable that per chat.
I have all chat images contained to only Whatsapp by default. Then I only enable some chats (family, friends) to expose images/videos to the phone.
Google Photos scoops those and backsup all family pictures shared to whatsapp to my Google Photos.
I'm the family's reliable source of truth when it comes to family photos.