Guitar turner app on my iPhone 13 is not working

I use an app called Guitar Tuna to tune my guitar. I couple weeks ago it stopped working and started behaving strangely. It’s still recognizing sound but not correctly identifying what string I’m trying to tune. I tried uninstalling and reinstalling it to no avail. I installed several different tuner apps and had similar issues with all of them. I had reported the issue to Guitar Tuna support but they were useless. Since I’m having similar issues with other tuner apps I assume the issue is with either with my phone itself or with the operating system interaction with the apps. Other functions that use the mic are working fine. Any have any idea what might be going on?

[Re-Titled by Moderator]