Real DS to emulated Pokemon trade / Mystery Gift?

I recently dug up my old DS and Pokemon HGSS cartridge.

However, I finished the game, so there is not a lot to do, that's why I wanted to start anew. Problem is, I would lose the Mystery Gift (Yellow Forest, Time Travel Celebi, and Arceus) and a lot of Pokemon I grown attached to.

While I maybe could try and search for another cartridge of that generation to save my pokemons, it would probably be faster to just emulate the game, and trade with that, with the additional benefit of backing up the pokemon themselves.

The other problem would be losing the Mystery Gift, I doubt Nintendo will (re)release those events at all, and I would love to be able to redo the Celebi storyline or travel through the Yellow Forest again. Recreating the mystery gift would only be possible with emulation anyway.

The solution I see are:

Buy another DS, buy used cartridge until I find one with a non opened Celebi Mystery Gift (costly and bound to fail)
Try to find a flashcard (costly, unreliable at best since the companies all closed, and a lot of fakes are circulating, and, last nail to the coffin, illegal in my country)
Use a action replay, which are not in sale anymore for DS, and that have no reliable seller.
Use a PC emulator and somehow make the emulator interact with the real DS hardware and cartridge for pokemon trade and mystery gift.

Is that last solution possible at all? Is there a solution that I didn't saw?

I saw a project that tried to emulate the Trade Center, but it doesn't work anymore since authentication to Nintendo was needed anyway, and those server are now closed definitely. Even if it worked, it would only have allowed me to save the pokemon, not the mystery gift.

Note: While piracy is off topic, emulation is, at the best of my knowledge, supported. I am only interested in finding a way to keep legitimately obtained events and pokemon on real hardware.

TL:DR: I want to use a emulator (preferably open source) to trade pokemon and mystery gift with a real DS cartridge.

Best Answer

While I maybe could try and search for another cartridge of that generation to save my pokemons, it would probably be faster to just emulate the game, and trade with that, with the additional benefit of backing up the pokemon themselves.

You're thinking backwards. That would not be faster or easier. You just a "pokemon box" type of storage for your Pokemon so you can transfer over to your newly created save on your existing cart.

If you have a 3DS you could use PKSM

https://github.com/FlagBrew/PKSM/releases

Then after that you can start a new game and transfer those pokemon back to HGSS.

Optionally, you could do what you originally suggested and use TWLSaveTool. Just because it's not maintained doesn't mean it doesn't work.

https://github.com/TuxSH/TWLSaveTool

Then copy the save over to your emulator.

NOTE: Wifi emulation does work on emulated DS (melonDS for windows). It's confirmed working with Pokemon. However, I do not believe you can connect to a real 3DS at this time. Read here for more information.

https://gbatemp.net/threads/after-several-years-ds-wifi-emulation-is-back.474947/