The video is excellent and I would encourage anyone reading this to watch it, but for the benefit of those who don't like clickbait the answer is: surround yourself with a quilt, jacket, pillow fort, or similar, because although it looks ridiculous it gets rid of background noise and muffles reflected sound.

(I haven't "saved you a click" because you should watch the video anyway. It's not just about how to get better sound when recording or broadcasting. About ten minutes.)

This is my problem. In order to get a decent sound in my untreated office (reverberant bare walls, hardwood floor, etc) I need to have my dynamic mic with a low gain setting and I have to be right up on it, which makes me look like I'm on Joe Rogan's podcast or something. For Zoom I'd prefer if you couldn't see the mic.

A lavalier hidden in your collar (or tie knot, if you're that kind of guy) might work for you. Because they're surrounded by clothes and your body it's less susceptible to room noise.

https://www.youtube.com/watch?v=D85HmR825wM