I’d like to print using my computer but also use the LCD to see the percentage of the printing.
Also it would be nice to resume using the rotary encoder when I have a M0 command in my gcode and printing through USB (it’s working when I print using the SD card).
This would have to be implemented both in the software streaming the print to the printer and in the printer’s firmware.
I don’t think you can just switch it on. The printer just gets GCODE commands over the USB to serial interface an executes them, it does not know anything about the state of the whole print.
If using cura use post processing to send updates to the screen