The M141 S50 gcode means that you set the chamber temperature 50℃.
So we could change Machine start G-code to set the chamber temperature.
Printer-Machine G-code-Machine start G-code
Step 1 Please add the M191 marco into the printer.cfg file.
[gcode_macro M191]
gcode:
{% set s = params.S|float %}
{% if s == 0 %}
# If target temperature is 0, do nothing
M117 Chamber heating cancelled
{% else %}
SET_HEATER_TEMPERATURE HEATER=chamber_heater TARGET={s}
# Orca: uncomment the following line if you want to use heat bed to assist chamber heating
# M140 S100
TEMPERATURE_WAIT SENSOR="heater_generic chamber_heater" MINIMUM={s-1} MAXIMUM={s+1}
M117 Chamber at target temperature
Where to find the Printer.cfg file: QIDIslicer-Device-Configuration-Printer.cfg
Add the M191 marco and click Save&Restart
Step 2 Enable the chanmber heating function in Orcaslicer