Yes it’s possible, but it’s not something you can easily scale.

I had a similar project a few years back that used OSX automations and Shortcuts and Python to send a message everyday to a friend. It required you to be signed in to iMessage on your MacBook.

Than was a send operation, the reading of replies is not something I implemented, but I know there is a file somewhere that holds a history of your recent iMessages. So you would have to parse it on file update and that should give you the read operation so you can have a conversation.

Very doable in a few hours unless something dramatic changed with how the messages apps works within the last few years.

If you mean hook this into iMessage, I don't know. I'm willing to bet it's way harder though because Apple