Hi! If you tap on your alarm in the "Clock" app, then tap on the words "Alarm sound', you will see the volume slider at the bottom. For your notification sounds issue, try this: Go into "Settings" / "Apps". Tap the dots in the upper right hand corner, then select "Show system apps". Scroll through the list till you find "Sound picker", and tap on it. Tap on "Permissions", then make sure "Storage" is allowed.
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