How come my iPad keeps saying not compatible with this device when I try to download an app
How come when I try to download an app on my iPod or iPad it says not compatible with this device
Perhaps your iPod or iPad have not, themselves, been updated to the minimum version of iOS/iPadOS that the App requires.
You will need to verify the minimum iOS/iPadOS version required by the App in the App Store (this being shown for every available App - you’ll find a drop-list). If your devices can be updated to meet the minimum requirements for the App, you should be able to install the App.
If your devices are too old - and do not support more recent versions of iOS/iPadOS, your only option is to replace the device with a much newer model.