Bluetooth switching out of time on assistant/calls

Ever since I switched to a new Pixel 8 (currently running Android 15), I started seeing erratic bluetooth behavior in these two scenarios, which look somewhat related: 1. Whenever I use the assistant button on my car, the appropriate volume is applied for the initial tone and then the response; however, the same volume level is temporarily applied to media playing before the assistant request, making it unbearably loud; 2. Whenever I place a call with a bluetooth device (car or headset), the end call tone is routed through the phone speakers, never the bluetooth device. These two look somewhat related, given they happen at the time the device is switching from a mic+audio mode (hands-free mode), to audio only (A2DP). As stated previously, I switched to Android 15, coming from Android 13.