Open Car head unit work around for google voice or bluetooth calling

Im using an android head unit in my car - the head unit does not have a sim so no 4g.

I connect my phone to the head unit with bluetooth. My phone reports the head unit is connected for media and calls and contacting sharing is on.

I have google assistant available on the headset and this works if i use my phone as a hotspot.

I would like to ask my head unit to "call Sharon" and have it place the call via Bluetooth.
Alternatively, have the request routed to my phone's voice assistant....
.... Or have tasker place a bluetooth call
.... Or have tasker trigger the media button event (since the head unit is acting as a headset)...

Or.... Some other workaround... A voice bridge from one android to another???

Does anyone have any ideas as this is causing me sleepless nights.

Id be really thankful for your ideas.

Rob