Reddit mentions of CP8201 Microphone Impedance Matching Transformer

It's probably overkill for this application and outside of your price range, but when I tried Dragon Naturally Speaking several years ago, I used a Shure SM58 with a cheap impedance transformer on a nice sound card. My accuracy was 95% and this was 10 years ago. I would check out Shure's SM58+X2U Combo. I'm sure in combination with the software advancement that you would see damn near 100% accuracy with this. An industry standard microphone compared to that cheap USB nonsense should absolutely make a huge difference.

If you want a brand name Amazon.com will get you an Audio Technica adapter for ~3k JPY including shipping.

If you want cheaper/no-name it's all random chinese stuff on ebay anyhow in which case you may as well get it from Aliexpress.

Edit: Well, I failed on the AT one, that's XLR to 1/4" and not even 3.5mm.

this is what you need

This is an "Impedance Matching Transformer", meaning it will match the microphone level to a line level. Here's some info on why you can't just use a normal adapter:

"It's not the best way to do it, but it works. People do it all the time. Microphones output a 'low impedance signal' whereas guitars output a 'high impedance signal.'

"This subject can get very complicated, but suffice to say that low impedance is microphones, and high impedance is line level outputs (synthesizers, guitars, amplified signals).

"Mismatching results in a very distinct tonal shift, or heavy distortion depending on the level of mismatch."

-Some dude on a forum

https://www.gearslutz.com/board/low-end-theory/343776-huge-noob-question-can-you-plug-mic-into-guitar-effects-pedal.html

Amazon link:

https://www.amazon.com/gp/aw/d/B0002CZYFC/ref=ya_st_dp_summary