If the show arrives at the system as a digital signal, then Audacity will let it all in on the assumption you wanted it to be that way. Sometimes you can change the recording volume in Windows control panels.
What’s supposed to happen is you have volume controls on your microphone interface or sometimes on the microphone itself.
Recording device is "Speaker Headphone (Realtec audio loopback)
When you select “loopback” you are accurately capturing the digital audio stream sent to your soundcard for playback so you can’t change the volume.
and I am unable to reduce the level.
If it’s “too loud” you can use the Amplify effect with a negative value after recording but that won’t remove any clipping/distortion present in the original audio.
What he said. You change the analog volume of a capture system (see pictures above) to avoid noise and overload distortion, that’s what the recording engineer does, but once the signal becomes digital, you’re stuck. If the digital sound is so loud it overloads, the best you can do is change the volume of the overload distortion. The distortion is not going away.
Try going into your Control Panel. From there, View Devices, and right click on your microphone. Choose ‘Sound Settings’. This should open up a new box entitled ‘Sound’. Click to the ‘Recording’ tab, and you’ll see all of your microphones. Select the one you want to record with and then click the ‘Properties’ box. Click on the ‘Levels’ tab and here you should be able to manually adjust your microphone input to the computer. It’s a bit of a faff, but gets around Audacity being stuck at 100%.