What Jonathan said. Countless people have tossed Noise Suppressors on their streams, and then wondered what happened to their instruments in church or sound effects in a game.
Noise Suppression is designed for spoken voice only, like a conference call by someone who understands absolutely nothing about audio or acoustics, and sits in the absolute worst possible spot, and still expects to be heard clearly with silence otherwise. Anything beyond a spoken voice is considered noise to be removed. (like if they sat directly under a lobby speaker...)
If you have one in OBS, of course take it off. But you could also have one in Windows itself. That one is on by default, because most of Microsoft's customers are business people and casual home users, both of which make conference calls with spoken voice only, understand nothing, and expect it to "just work".
So for most of MS's customers, it does "just work" because that function is on by default. You need to find it, along with all of the other "audio enhancements" that Windoze or your audio driver might have, and turn it all off. Anything that is not "a straight dumb wire" needs to go, no matter how deeply it's buried to avoid nosy people stumbling onto it, fiddling with stuff with no record of what they did, and then blaming Microsoft for wrecking their conference call.
