I haven’t done a proper check, but most of those codes seem to be low-speed-CAN bus (aka GM-lan) related. GM-lan is a single-wire (and uses the body as a ‘return’) CAN bus and it is mostly used for non-speed/time-critical applications in the car such as the instrument panel, HVAC, radio and many of the creature comforts.
The tricky bit is that a single faulty module anywhere on that one-wire bus can disrupt the whole system. Also, a single short to ground of that one-wire bus will also disrupt the whole system. It’s actually a tricky thing to diagnose, so beware, it might cost more than a single kidney.
What I’d be doing is firstly having a good look (i.e. visual inspection) around the electrical system looking for any signs of physical damage. It’d be a bit of a long shot, but if any signs of physical damage are found, then dive in deeper.
The other approach is to start disconnecting modules and clearing codes until the GM-Lan comes back to life. For example, disconnect the radio and see if (most of) the errors disappear. You might get an error that the radio is ‘not found’ but that is to be expected. Continue disconnecting modules (HVAC, HUD, whatever else that is in the error list) until the communications error disappears. Plug the last item back in and verify that the error returns. The hard bit is accessing the various modules as they are buried away in different parts of the car.
The other possibility is the BCM itself. iirc, the BCM is the ‘bridge’ between the various CAN busses in the car, so if it fails, it will result is a widespread communications error.
