Update to this...
Found a very few, select comments scattered about the web from others that seem to confirm the limitation of iPhones and Android only being able to have (1) WiFi Direct/wireless connection at a time creating the auto connect/disconnect issue I was seeing.
** No clear mention of this on Blackvue, Dashcam Store, or BlackBox My car sites that I could find. **
Was able to go into the Android Auto app while disconnected from the truck and turn off wireless android auto setting....
** With that disabled, I was able to use the wired USB connection and also keep the WiFi direct connection to the Blackvue Camera while driving (not really needed) and was finally able to setup the cloud option/account via my phone's hotspot & home WiFi (can't seem to get the Blackvue to see the truck's hotspot for some reason?).
Went back and turned on the AA Wireless function since I don't need to be connected all the time while driving.
Was also able to use the Blackvue PC app at the house (garage) to connect to the camera via home WiFi and see various footage, download it, change dash cam settings etc which is very convenient.
May have to consider getting the LTE add-on module with a prepaid sim for trips, etc away from the house to keep an eye on things down the road. (considered the 750 LTE version but it doesn't seem to have the current/newer parking mode 3 wire hardware kit without getting the add-on magic power box). ** If you are cloud connected with a data plan for the camera, you can connect/view that way AND keep your AA/CP wireless connection.
** If anyone knows a way to get the Blackvue Camera to see the truck's 4g ATT hotspot, let me know ?? **
PS:
someone mentioned an MCX Female to MCX RT Angle Male jumper to clean up the back camera wiring a bit they found on eBay (thanks).
Found a nearly identical 12" one on Amazon for $10 with a quick turnaround...
Aoje-Link RF Coaxial Cable MCX Female to MCX Male RG316 Coax Cable Jumper for DIY Radio, 3G/4G/5G/LTE/Antenna, Audio and Video Signal Transmission, 300mm 1Pcs
.
And resharing the interior fuse box reference from earlier posts with my notes on it.