All along, if i’ve been recording off, say, YouTube using WASAPI, i didn’t need my speakers turned up.
Now, for some reason, the input level on my recordings is based on how loud my speakers are turned up, with my computer saying the app is using my microphone setting (there is no microphone plugged in in the port). So, if i turn my speakers all the way down while recording, i get zero on the audacity. What’s changed? and how do i get it back it the original setting?
What’s changed?
Possibly a Windows or driver update.
It seems to be inconsistent but most computers work like yours where the playback volume does affect recording volume. With WASAPI (loopback) you are recording what’s coming out of the soundcard.
If you have external analog speakers they usually have a volume knob or you can plug-in headphones and put them in a drawer if they are still too loud, etc.
with my computer saying the app is using my microphone setting (there is no microphone plugged in in the port)
Your Audacity Recording Device should be your soundcard output or “speakers”, etc. and it should say “(loopback)”. Audacity will always show the microphone icon to represent the recording volume and the recording meters.
If you have a laptop, don’t select the microphone. 
If you have a desktop/tower with no mic, of course it can’t be recording from the microphone.
It may or may not be relevant but recent windows 11 updates have moved mixer controls in to windows settings. This includes the separation of system sounds volume settings and app sounds volume settings which can be different for each app ( e.g. the browser you use ) . On my system app volume changes the wasapi output level but system volume does not. My USB speakers also have a physical volume control which does not change recording level.
Thanks for that possibility. I’m still running Win 10 though, so I think I can rule that out.
The other thing i’ve noticed is this: I set my screen to switch off after an hour. But now, with Audacity simply open (nothing happening, no open files, nothing), the screen won’t switch off. It’s very bizarre to me.
I think it was established a while back that when a multimedia program is running, the screen never powers down. This is to prevent the screen from turning off when playing a long duration DVD. It is done by the operating system and is not a setting in Audacity.