Choose a double DIN CAR radio

Vehicle is GMC 2006 Sierra 2500 Crew with onstar , steering wheel controls and Bose system Basic double DIN Am FM cd player radio.
Minimum requirement bluetooth , android and apple access thru USB and wireless.
GPS installed OR thru a phone application? Will go off grid so would need with only satellite access.
Maintain steering wheel controls and BOSE speaker system.
At least a back up camera but would like more cameras.

Im overwhelmed with choices and found no methodology in the way to compare one brand / model over another..

Looking at past year or two older models to get a head unit for under $500

I was looking at Pioneer AVIC-W8400NEX Double 2 DIN DVD Player GPS Bluetooth HD WiFi CarPlay or Kenwood Excelon DNX695S 6.8" WVGA Navigation/DVD Receiver. Both new under $450

Then in doing more research talking directly to Pioneer / Kenwood then to stores Like BestBuy / Frys they only provide the latest model or one in stock.

Now I have recd many recommendations from Pioneer AVIC-W6400NEX Double 2 DIN DVD Player GPS Bluetooth HD WiFi CarPlay , Kenwood eXcelon DMX906S Digital Multimedia Receiver , Pioneer AVIC-7200NEX DVD Navigation Receiver and a half dozen more.

Will install myself.

Please advise.