My iPad Pro gen 3 does not pick up sound from my guitar

Hello! I recently tried installing a couple of popular guitar tuning apps on my iPad Pro Gen 3, which I used to use on my iPhone. However, the apps don’t seem to pick up any sound for tuning or even for lessons. I checked the app permissions for the microphone and even recorded using the built-in recorder app to check the internal microphones. All of these seem to be working fine, but whenever I install an app that helps me tune my guitar or where I find guitar lessons, it doesn’t recognise the sound. Interestingly, I found that if I tap the iPad with my fingers, the app notices the sound through the built-in microphone. I’m desperate for help because I have limited days left on my subscription. I’ve tried several popular apps, and the issue persists. Could you please assist me with this? Thank you.