Thank you so much!
Ok, I attempted to change the CNAME as you suggested. It may take over 24 hours to see if it worked or not, though!
What I’ve done the other day is asked bluehost to add retouch.katerinamarie.com as a subdomain, as well as asked them to add SSL to it. I had followed this tutorial from 2023 to set up multisite: https://kinsta.com/blog/wordpress-multisite/
What can I do to install another instance of wordpress instead? I only have my one website domain to use at the moment, so I’m not sure if that limits me.