Loud buzzing noise in recorded audio?

[Poke]

After receiving my modded 3ds in the mail (thanks, Loopy, the visuals work like a charm!) I decide to test it out. I notice it picked up my microphone so I unplugged it and plugged in an aux cable between the 3DS and the computer's microphone port. However, to my surprise, the recorded audio had an extremely loud and obnoxious hum to it! No matter what video encoder I used, the audio hum persisted, and I have followed every piece of advice I could find. Can anyone help me with this?

Here's what I'm dealing with, recorded game is Pokemon HeartGold. https://www.youtube.com/shorts/bguBNMEqXKk

[Poke]

Update: I managed to make a workaround by using the program Voicemeeter Banana by turning the desktop audio into a microphone input. By doing this (and minimizing all other sounds) I can record footage with audio without the use of an aux cable. Audio delay is either nonexistent or negligible, too, so it all works out.

[TiresiasBazaar]

Have you considered trying a Ground Loop Noise Isolator? I used one to remove the static from the audio, and it works like a charm too. I know you found a solution, but I'm just throwing it out there.