As a general rule you should assume everything you put on the internet is accessible. Unless it’s encrypted by a key you provide, and I mean a full rsa key, it’s going to be accessible.

The notion of privacy on the internet is not a thing. Everything you write is going to be collected and aggregated, especially in the world of AI.

What you can do is use an alt account with no info, and if it’s really sensitive use a VPN to hide where it came from. For private messaging do not use anything but an encrypted chat service.