We have the exact problem. Our congregation replaced the main laptop used during services and I thought it was Windows 11 that was on the new laptop and set it to Original Sound without improvement. I even added an external mic, still poor with "muddy" sound as Zoom seems to mute the vocals. I was sure it was Windows 11, but we noticed on the second laptop which Windows 10 and had been working very well up until the last few months, now as the singer raises her singing voice the mike almost completely mutes. Setting this laptop to Original Sound has no affect. When I set Original Sound while using the cell phone works as expected and substantially improves the sound, but comparing enabling Original Sound on the laptops seems to produce no detectable change. There is something wrong with Zoom and it's interaction with Windows. This changed for us about 4 or 6 months ago.