Within QGIS Python console, get the ini file from QSettings
settings = QSettings()
print(settings.fileName())
Then in your Python console, use path from above settings.fileName() like below
from PyQt5.QtCore import QSettings
settings = QSettings('/home/thomasg/.local/share/QGIS/QGIS3/profiles/try-out/QGIS/QGIS3.ini', QSettings.IniFormat)
# Now working
print(settings.allKeys())