I hope you checked the screen in the expansion valve. It is known to sometimes clog.
did you add a hi/low pressure cut out switch to the refrigerant drier? They were common on most AC systems but not on our cars. Easy to install and simple to wire The high pressure would happen on an icing condition that blocks refrigerant flow, and the low pressure would happen in a refrigerant leak. Both triggerpoints will open the power to the compressor preventing damage
The expansion valve coil that clips to the evaporator line is in charge of temperature control by regulating the flow of refrigerant.
The switch commonly referred to as the temperature switch is technically a thermostatic switch. It has a capillary tube that is inserted into the evaporator coil.
It is designed to open the compressor power circuit if it senses a low enough temperature that might cause atmospheric humidity to freeze on the coil. By disabling the compressor the system temperature rises and the potential icing condition is avoided
less than full clockwise rotation tells the switch to open the compressor power circuit at a higher temperature than an icing temperature
there is likely nothing wrong and no troubleshooting required
Larry