My iPhone 11 running iOS 13.3 won’t give permission to apps to use my camera or microphone
Photos and Camera are two different settings, access to the Camera doesn‘t automatically grant access to the Photo library as well. There should be a separate option to enable for Photos, e.g. for WhatsApp it looks like this:



You can try to tap on "Enable Library Access" (from the second screenshot). If this doesn't work I would proceed with reinstalling the apps in question and trying again.