How do i programmatically update content in SquareSpace?

Foreword: i am very very new to square space and also to CMS in general. so please pardon any "dumb" questions

Let's say i own a squarespace page. Let's say i want to randomly update the home page with a random greetings every day (or every 2 days..etc.) I feel that since this is a CMS, the right way to go is to basically somehow set up a remote server that can scp into my specific square space server instance. the remote server will update some file (or generate some content), and scp the "index.html" file over to the square space instance.

alternatively, if i have my own server running at home, it looks like i can write some bash scripts to modify (commit & push) and deploy using git??

is this the right idea? what other CMS services provide this?