Newb question: finding my hosted databases

Apologies if this is a really stupid question. I'm very new to SQL databases and I need some help. I work at a book store with a website hosted on an AWS EC2 instance. Nobody touched their website for a long time and now we're in the process of updating it. It appears the book data are stored in a posgresql database hosted with a different host name than the domain owned by the bookstore. I've tried looking in the ec2 instance using

systemctl status postgresql

and there is an active sql DB that doesn't match the domain name, does match the database name and seems to be performing SELECT queries that look like what I'm expecting for a row entry for book data. How can I confirm this is the right database, how can I check for the database that is hosted under a different domain name to see where it is (and prepare it for backup if needed for a staging site). I'm going through Google, ChatGPT and I'm even currently doing a postgreSQL Coursera course to get the info I need. But as I said I'm very new to all this and I don't want to hurt anything on the live instance. The site wasn't touched for ten years, is poorly documented. We're prepping to get a software development team in to finish the upgrade, but as it stands I just need to make sure our database isn't hosted by an old contractor that could delete the entire DB at any moment.