How do I trade Pokémon between two emulated generation 4 games?

I want to know how to trade Pokemon between 2 Emulated generation 4 games like Platinum and Heart Gold, but as far as my research showed it is only possible through GTS, which is shutdown, so I can't trade in emulators in gen-4 games.

Does anyone know a way to make it possible without faking it? (Faking it means using stuff like PokeGen or spawning the Pokémon you want to trade in a route through cheats)

Some Things to know:

• I have a Laptop
• I have a Phone

MelonDS emulator should work with union room but from my experience, it's unstable. You might have to resort to online trading like GTS or wi-fi club which have been resurrected by players and can be used if you connect with the right DNS (even mystery gifts work with this). Check out pokemon classic network for example, that seems to be the most reliable one.