Missed notifications when bluetooth headset is paired.

I use a bluetooth headset (blue parrot, noise cancelling on the ear, works with the wind howling past me in a car or on a tower). When it's paired and hanging around my neck or laying on the desk beside me because I'm not actively using it at the moment, I get no notification sound that tells me I have a new text message. This is a "very bad thing" (tm). I don't see any setting in my iPhone to tell it that it needs to always make noise on the phone's speaker for notifications.

I'd also like to be able to tell it to play media over one bluetooth device and phone calls over another. The bluetooth in the car sucks for calls. The headset is perfect for calls and sucks for music/driving directions. I cannot find settings for that either.

This was all very simple on my Samsung Galaxy S7. Unfortunately, it died and work wanted me to be able to share an iCloud calendar. Getting over the learning curve to make the iPhone half as useful as the Android for a sysadmin / wifi installer has been challenging so far, 2 months in.