No Notification Sound When Receiving Texts

Hi, I own a I Phone 15 Plus and in last few weeks my phone has not been notifying me via sound when I receive a text or any other app notification. I have restarted my phone several times, disconnected it from bluetooth as I have a fitbit and I use bluetooth headphones, did a new update and have continually checked for haptics and sound settings, nothing has helped so far ! I am getting really frustrated as when I am setting up the volume low or high, through the notification settings it’s working just fine ! If anyone is facing the same issue or has found a solution to the same, please let me know ! Thanks very much in advance !