Hello, thanks for trying this app (I'm not the developer, just sharing it here).I have 2 weird problems.
1st sometimes when I open the app the circle loader appears like the one that appears when hdr is processing even though I haven't done anything yet.
2nd sometimes when I press the shutter button nothing happens for 5-10 seconds and then the photo is captured.
As said a few posts above, your problem might be related to Android 11, as I'm not facing this with this app and xml with my A10 Oneplus 8 Pro (I'm willingly keeping A10, for better compatibility with Gcam apps). Anyway, you might want to try something in the settings. First, go to Advanced, then to Device Model, and finally try to change the Interface Style to another one. This may affect the IQ results you get with this app too, so it's just an experimental workaround.
Hope it helps.