Hello,
Yes, I would recommend trying the bootloader procedure anyways, maybe that would be enough to bring the modems back.
As the global RMA rate of our devices is only 0.05% of all devices manufactured, I would be highly positive, that the RUTX14 ordered will have no issues whatsoever. However, this percentage also means that some devices being faulty is not inevitable as we sell hundreds of thousands of devices worldwide and this can happen due to some faulty component on the device PCB. We are always happy to solve any hardware-related issues as fast as possible and our RMA is usually quite fast.