I've hosted this too on my NAS. Works fine.
Important: You need to edit the launch.json
"server_addresses": ["0.0.0.0:2345"],
or else I couldn't open the site. This also allows us to only expose port 2345.
I use TrueNAS Scale, which doesn't allow custom apps (through the wizard) to set the working directory. To workaround this you can either use
/bin/bash -c cd /game;wine marvel-lcg.exe
as the command or alternatively create a run script and use that.
Would be great to get a native linux version so it shows logs/is more efficient than running it through wine.