Hello, I asked the team about this, and was informed there unfortunately isn’t a solution at this time
This seems counter-intuitive if I'm being honest. There's more players using Linux these days than when Rebellion was first released all those years ago. Then there's also the Steam Deck.
If I could find a solution for why the Stardock launcher kept disappearing on my Linux with a simple fix by making gamedata2.dat file read-only then I'm certain there can be an easy solution to the multiplayer issue. Link
And If I'm being honest, Sins of a Solar empire has always performed better on a linux computer than a windows due to the fact that there was more system resources available within the constraints of the memory limitation and architecture. Sins 2 doesn't have that limitation but Linux is still better for performance. I guess what I'm trying to say is, the developers may want to invest in supporting Linux if it's something to consider.