tool to do it ( https://github.com/barronwaffles/dwc_network_server_emulator/wiki ) – it can work with both consoles and emulators (make sure to change DNS)
there is a community around this in case someone's interested https://discord.gg/ma4vzx6yaD
i'm not caught up with dolphin's netplay state rn, so i might be outdated on this front.
https://www.youtube.com/watch?v=KGIeo3Vols8
Source: r/tenkaichi4 · by /u/otto_maitre_de_heroe