When you connect the left joycon as a single controller, the button mapping is all wrong. You can fix this manually in the settings in steam by remapping the buttons. The right joycon does not have this issue.
You do run into a problem with the joystick if you remap the buttons. since it will need to be reverted in the y direction, but steam seems to save the setting wrongly. What you do is:
setup device inputs and complete the guided setup -> copy to clipboard -> paste in text-file -> find section that says lefty:\~a0 and replace with lefty:a0\~ -> back in steam, setup device inputs -> paste from clipboard
This is a similar issue to , so I believe it to have the same root cause.
When you connect the left joycon as a single controller, the button mapping is all wrong. You can fix this manually in the settings in steam by remapping the buttons. The right joycon does not have this issue.
You do run into a problem with the joystick if you remap the buttons. since it will need to be reverted in the y direction, but steam seems to save the setting wrongly. What you do is: setup device inputs and complete the guided setup -> copy to clipboard -> paste in text-file -> find section that says lefty:\~a0 and replace with lefty:a0\~ -> back in steam, setup device inputs -> paste from clipboard
This is a similar issue to , so I believe it to have the same root cause.