Is there any simple way that I can see what sites my databases are connected to, and which ones are not connected to any sites, preferably through the dashboard?
If that's all you need, try one database at a time with a error thrown in, perhaps a wrong password on purpose, or similar. Then you should see which connection Just errored.
Definitely have good names for everything that makes sense.
Because that's going to take a lot of time when I have 70+ sites - I'll have to FTP into each WordPress site to get that info
It boggles my mind that there's no simple UI in the Forge dashboard showing this information that clearly exists - there's a list of sites, a list of databases, a list of databases users, but nowhere stating "this site uses this database" 🤯