Hi,
It seems that one of the JSON config files is corrupted.
Please try the following:
1) Rename Publii/config directory to Publii/__config – if Publii will start then we will need to check your app config files
2) If above point won’t help – please rename Publii/sites catalog to Publii/__sites and create new empty Publii/sites catalog. If Publii will start properly, then problem is connected with one of your sites configuration.