iPhone XR Bluetooth connectivity issue

Hi, I am facing some problems with my iPhone XR especially regarding Bluetooth connectivity (among other things) - coincidentally this happened after I updated to iOS 15.2. All my Bluetooth connection devices (including my Airpods Pro) will not connect unless I put it right next to the top/ bottom side of the phone. I've toggled Bluetooth on/off, done both soft and hard reset, as well as run mobile diagnostics with Apple technical support both online and in person - everything points to my Bluetooth connectivity working properly. I am wondering if this is a software bug/ systems issue or a hardware issue. Has anyone faced a similar problem? Thank you.