An app without tethering would be great, I agree. But to save space on your phone, it's easy to turn off automatic storage of media, on iOS this is under Setti

An app without tethering would be great, I agree. But to save space on your phone, it's easy to turn off automatic storage of media, on iOS this is under Settings > Chats > Save Incoming Media. I've had it turned off for a long time to stop my camera roll filling with meme pics.