I just got a 2021 suburban last week, and today this problem started. What was interesting is that I was pairing my phone right before I hit reverse, , so really made me wonder if that was part of the problem But unpairing, turning off phone, waiting 1 hour, etc, still same error screen when the reverse is hit.
What has me concerned is the fact that you are still waiting without this functionality, seemingly for months. To me this is a safely issue (what would your insurer think f they knew your backup camera wasn't working?). Your car (and mine) is not functioning as intended, and your Chevy service left the vehicle with you. As you may or may not know, when a car is in for repair for 30+ days, it qualifies as a lemon, and the dealer is required to replace or buy the vehicle back; at your full cost (minus your usage (at time of first repair visit)). Alternatively you are entitled to some $$ compensation which can be substantial (if you waive the right to lemon law). The compensation and or buyback includes and rental car expenses, etc. But since you have the vehicle, well, it is perhaps not "in for repair". You may want to contact a lemon law attorney for a quick consultation,.
What I am wondering is can the dealer/service require you to take the non-fully functioning vehicle back when they cannot even repair it and are "waiting to hear from GM"?? I would want an equivalent loaner or rental, and they have it until they fix it, even though I would prefer to have my own car. If the car is unsafe and most importantly not working as intended, they should fix it, period.
This has me seriously concerned. This vehicle is 8 days old!