Since I'm incredibly lazy, I'll suggest / ask ...
Have you considered installing a ~$25 AUX input to the existing stereo, followed by plugging a $4 bluetooth-to-AUX interface on the end of that?
Current thread on someone doing current research on an AUX adapter.
anyone have success with this (or something similar) https://www.amazon.com/Interface-Yomikoo-1998-2002-1999-2005-1999-2004/dp/B01ALDYGEG/ I've read some posts here about an "aux box" fabricated by a user on the forum but not sure if they still do this. if anyone has had success with similar...
www.odyclub.com
My response there tells my 2008 solution for the AUX input, which is still working great. And after reading your question, I now realize I am now only a $4 bluetooth adapter away from winning another World's Greatest Dad award from my kids. They will think it's a new car.