I have the same problem as OP: Mk3 2016 Bolero MIB1 control unit broken. Since I'm not going to shell out the 1450 € for a new part, I'd prefer to replace it with a second hand Bolero model. The Skoda retailer said that they can reprogram a used part so CP and feature enablement shouldn't be an issue.
Most threads here seem to be concerned with upgrading to Amundsen or Columbus but I have no use for navigation. However, better than original parts seem to be readily available second hand, so I wonder which parts can be used with this. Can I go for MIB2 or Amundsen/Columbus units, while keeping the original display and Canton modules, and without resorting to CP removal hacks?
The retailer also told me that they had another car with the same problem, the control unit dying for no apparent reason. If this is a common problem, I also wonder whether anyone has managed to repair the unit. Mine went dark a few times first but resumed normal operation for a few days before finally dying. All of this started when the car battery died, and after a week or two the radio was gone.