Software/Hardware testing protocol

Stackoverflow users!

There is a developed device with a huge amount of different configurable options, which can be set either separately or simultaneously, some of them exclude the usage of others. The device is configured in GUI.

The problem is that after each firmware release, new errors appear, so the device has to be tested before the firmware release, but for now it is tested with random settings, how to organize this testing procedure in the best way? some test protocol, etc.?

Regards, Andrii