The source code to the software doesn't help much. It doesn't document design decisions that can relate to electrical or mechanical properties of the device.
I am not agaist a right to repair in general, but what I want to see is pretty strict regulation that repairs to potentially hazardous devices may only be performed by trained professionals. E.g. the brakes in your car would be off limits anyone except a licensed mechanic. But manufacturers would have to supply documentation, tools and spare parts to any qualified mechanic, not just their own dealerships.