Confirmation regarding the theories on location based invisible content/messages:
** I clicked on the “remove restrictions” button and completed the “are you a robot” type questions. My account is back to normal now
TLDR my messages were invisible to my friends, and my posts were completely invisible to my friends when they clicked on my profile. After many days trying to reach a human agent (I didn’t manage to reach a human), I got this message.
EDIT: it’s been confirmed that my posts are visible to American users. One Chinese friend contacted their American friend who was able to send them a photo of my post (where I tagged customer support regarding this issue)