On Linux it is possible to define the port via start parameter.
/opt/Snapmaker Luban$ ./snapmaker-luban --help
Usage: snapmaker-luban [options]
Options:
-V, --version output the version number
-p, --port <port> Set listen port (default: 0) (default: 0)
-H, --host <host> Set listen address or hostname (default: 127.0.0.1) (default: 127.0.0.1)
-b, --backlog <backlog> Set listen backlog (default: 511) (default: 511)
-v, --verbose Increase the verbosity level (-v, -vv, -vvv)
-w, --watch-directory <path> Watch a directory for changes
--access-token-lifetime <lifetime> Access token lifetime in seconds or a time span string (default: 30d)
--allow-remote-access Allow remote access to the server (default: false)
-h, --help output usage information
/opt/Snapmaker Luban$ ./snapmaker-luban -p 12345
As a result it runs on http://127.0.0.1:12345/#/3dp
Should be possible with windows, too.