Alert volume is very low

Hi my alert volume or notification volume is very low, even though my ringer volume is max. So basically when my phone rings, it's volume is high but the notification volume is low, how do I increase my notification volume. I have checked the settings section everthing is set at the max i.e alert slider is max. My phone has the latest update 15.6.1. Please tell me how can i increase my notification volume. Thanks. P.S using iphone 13