- When not logged in on the laptop: Closing the lid of the laptop would kill the ssh connection; and laptop would not wake after re-opening the lid.
- When logged in on the laptop: Closing and reopening the lid of the laptop gives color noise
This solved both the ssh connection and made sure the screen woke up again after re-opening: https://askubuntu.com/questions/1059705/keep-a-laptop-running-with-closed-lid
Closing the lid for a long time when logging still gives color noise. Apparently it is an issue with the open source driver. There is however a NVIDIA proprietary driver. More about that later.