It looks like this requires a physical display adapter (with a dummy plug in it to spoof EDID) to create the display "instance" which Deskreen then copies to the remote device. So no, you don't have 25 video ports to stuff dummy plugs into.

Depending on your host OS, there _may_ be a way to create more displays that don't require physical video ports, but that doesn't seem to be documented or supported here.

Edit: OH! It's discussed here: https://github.com/pavlobu/deskreen/discussions/86