How can I stop hidden photos from showing up in my camera roll on WhatsApp and Instagram Stories?

I’ve got the iPhone 16 Pro, and I have some photos I wanted to keep private so put them in a hidden album but whenever I go to share a photo from my camera roll to my Instagram Stories, or via WhatsApp, they’re there for all to see. I’ve got wedding dress photos I don’t want my partner to see and if he uses my phone, he’ll see them.

I’ve got photos of a recent surgery scar that’s healing and I’ve taken progress shots and I don’t want to see them unless I choose to go into that hidden album. It’s not nice to look at yet I’m forced to see them whenever I go to share an Instagram story or want to send a meme to a friend on WhatsApp.

Literally *anyone* could see these photos if I go to upload a photo while sitting next to them and they happen to glance at my phone. Why aren’t they hidden from my camera roll via Instagram/WhatsApp, but they’re hidden from my main camera roll? Is there a way around this? I also can’t seem to delete the photos.

On a separate note, why isn’t low power mode automatic anymore?! Is there any way to make it automatic?

Honestly, I’m finding a lot of the changes on iPhone 16 are really irritating and not at all user friendly. I’m UK based, if that’s at all relevant for getting help or answers here. Thank you!