I'll add my very biased opinion here.
If you've an Android phone, there's a developer option that disables the Bluetooth absolute volume. It can help with lack of control from your current head unit. Can't say if Apple has this option.
Bluetooth is a must for me too but so isn't sound quality and functionality so I use the Kenwood excelon series head units. It has the wireless and wired options for both apply play and android auto.
With my 02, there's no vehicle management integration so I can't use those features, but the Bluetooth feature for my phone is crystal clear. The HU allows for the call to be sent through either the driver's side speaker only or all four speakers. It also has multiple volume controls for all the different input/outputs so my radio van be low while my calls can be at a higher volume as well as dual zone controls for the rear radio or video output if used.
It also comes with the camera connections for dash, rear and front, but more importantly the internal amplifier is very clean which helps with the BT clarity.