I can’t seem to print with only the right extruder, ensuring that I choose single 02 in both the slicer and the printer. Extruder 1 always seemed to print. I can copy or duplicate and the right extruder works. I was able to use only extruder 2 (right) in the past. Don’t understand what has changed. I tried looking in the GCODE when I did a single 02 print (looking for T1) It’s not there.
After selection single mode 02 on your SV04 display the printer should direct all g-code to the right extruder.
You may want to check your slicer settings for any custom start g-code that uses M605 commands. This could override your prior settings on the SV04 display.