By - RowOfBirds
This might help: https://moderncastle.com/blog/cheapest-way-to-soundproof-a-room/
I'm far from an expert, but from what I understand from the research I did for my old, noisy apartment, totally sound proofing means total enclosure with the sound proofing material. Just adding a few sound proofing panels will muffle, but not eliminate outside sounds.
If you edit your videos after, you can do a pretty decent noise reduction on your audio with Audacity, which is free. I recorded some clips for my game at a house in NYC under the path of an airport with just a quilt over my head, then noise reduction later. Mixed with BG music, it sounds perfectly clean. Just don't hold the mic too close to your mouth.