Codes U0100, P0700, U0073, U0101, C0040-04, U0137, U0140, C0242, U0101, B1325-03, B0086-05B101D-F0, U0121, U0131, U012A?

Hello, most of these are related to lost communications with module codes, which is probably setting all the other codes if modules are down on a network. 15.43 is a bit high but some newer vehicles do run at higher charging system voltages, still load testing the battery would be a good idea. Also see where it's at with the truck off. Does the vehicle run at this point?
Service info states 12-15.8volt is normal depending on what charging mode the vehicle is in. So, we need to deal with why the High-Speed data bus is offline. Most likely this is either a bad module pulling down the network which is very common on these, or the network is shorted to power or ground somewhere. I would start with checking the Trailer Brake control module and the Chassis Control module, I believe these are the 2 modules that will be under the vehicle towards the rear, and they are exposed to the elements the most. You will see when you find one, look above the spare tire as well.
With the key Off, you can unplug one of the modules that's under the vehicle, erase the codes and see if the network comes back.
We would use an oscilloscope in this case because the data bus can be monitored while unplugging modules to see if it comes back right away, but I'll go through and see what the rest of these codes are for.
These are all the modules offline right now, (or lost communications with). They are all on a High-Speed network (BUS A).

This is the full list of codes and their definitions. But the first concern is getting the network issue taken care of. These network wires will be a twisted pair and must remain that way if a wire repair is needed due to a short. The twisted pair needs to be exactly the same as the rest of the wire to prevent interference on the network. This vehicle has a ton of modules, 8 pages of modules, that are all on various different networks, too many to list actually, but all this critical modules like the ECM, ABS, BCM, etc are all on a high speed network because they have to do with safety. Ill try to break down some of these wiring diagrams, but I would start by checking any modules you find under the rear of the truck, those are very common areas to have trouble. Look for any corroded connectors or connectors with dirt or water in them.

Another check you can do, is if you have a capable scan tool, is to try going into each module that is setting a No Comms code and try reading live data. Since the scan tool may communicate on a different circuit, you may be able to get into these modules and see if any live data is available. If this works, try each module until you come to one that doesnt allow you access. This can narrow down your search for a bad module. This may or may not work, depending on the network fault occurring

https://www.2carpros.com/articles/can-scan-controller-area-network-easy