I don't know if this is helpful for cross platform, but for many games with problematic multiplayer you can use https://www.zerotier.com/ https://www.zerotier.

I don't know if this is helpful for cross platform, but for many games with problematic multiplayer you can use https://www.zerotier.com/ https://www.zerotier.com/ (works great for original Warcraft III) and they have a linux version.