2022 GMC Sierra AT4 blow amplifier and then the On Star stopped working

My husband has a 2022 GMC Sierra AT4.  Last week he got into the vehicle and there was absolutely no sounds, no radio, no blinker, no door is open, no seatbelt, NOTHING.  He was told the amplifier was blown and it would be almost $900 to repair.  He had the part replaced and now the On Star module isn't working either, as he noticed when he could no longer use his hot spot.  Since the warranty is up, the truck is back in the shop with another $225 diagnostic charge and likely another significant replacement fee.  I'm reading a lot of very similar situations here.  Why is there no recall and/or what could cause both of these things to go at the same time.  Of course the dealer is saying they aren't connected/related, but the timing is a little too coincidental for me.  Thoughts?