Fake a LAN connection? I've played with someone using an unusual acquisition method and bg3 literally just let it happen over lan, 0 fucks given and no work around. That was about a year ago, though.

Use zerotier/tailscale to set up a VPN/VLAN between your desktops with almost no effort (think modern day hamachi)

Have you tried just giving the friend MP code and them joining through it? Worked for me without any zerotier, so it could be repack dependent. I used the GOG version.

Pretty sure even pirated copies can make a Larian account and add friends thru that.

The game is DRM free. Nothing is stopping you.

just get GOG version and you can just direct connect to your lobby with code

I had it on GOG and played with my Steam friends via the code for the session, i imagine it would work? But i may be terribly wrong on this, so dont take my word on this

Assuming it’s GoG just play… verify your installer though

I think you all need to be playing the same version to play together.

The smart one among you, the one who pirated, has a headstart. The rest of you need to get your act together, pirate it, and then use something like Hamachi to simulate a LAN environment. This will allow you to play online together without having to pay for it.