llaspina 19 Light Poster Team Colleague

I think you need to give us some examples. What do you mean by "background?" Are you creating a GUI swing app? If so, then the assumption to use JPanel (or JFrame) makes sense. But you can create a GUI app with JavaFX if you are being more modern and you could use the java.awt package if you took some book out of the library from 1998.

llaspina 19 Light Poster Team Colleague

I'm not clear on why a database is being used at all. Is there no server component, just different clients for the various players all syncing with the same database?
I would have the clients all communicate with a server (either with TCP if this is running on a LAN or http REST calls or web sockets). The state of the deck could just be kept in RAM by the server and all the latency problems go away.