Has anybody tried hosting the DB on a server while running the application locally? Do you guys think that would be possible?
you can host a ZEO (DB) Server anywhere and let your instances connect to it via IP/Port.
So yes, hosting it in the Cloud is therefore also possible.
can explain how to connect my instance via IP/port instead of local ZEO (DB)
The IP will be the IP of the machine you are running the instance on. The port is by default 8080, but can be changed via the site’s buildout.cfg file.
Therefore, suppose your IP is 220.127.116.11 on a local network and you left the port number defaulted as 8080, you would connect to the site using a browser by navigating to http://18.104.22.168:8080
However, to connect over a WAN you will need to broadcast the site on port 80 or 443 for http or https respectively using a webserver like NGINX. Senaite is hosted this way the same as all Plone sites are, so you can refer to the Plone documentation on hosting a site via NGINX for setting it up.