I searched it up and it seems to be non-existent. If anyone can find one, that would be great.

I'm too lazy to explain everything again, so : https://www.speedrun.com/Streaming_Recording_Equipment/thread/d649e

In this thread we discussed about GBA, DS, and also mentionned 3DS capture cards (capture boards in DS & 3DS' cases) You'll definitly find your answer there.

Only person who made 3ds cap-boards went "out of business" so unless someone is picking up making them, they're only going to become more rare^^