Subaru transmission noise?

I own a 2001 Subaru Forester with 192K miles and the original clutch (only slips once in a while). Over the last couple of years, a noise has gotten gradually louder. It sounds like a wheel bearing that gets louder over time; however, it’s not related to the wheels turning. I can “feel” the noise when holding the gear shift. It makes the noise when sitting still in neutral. If I depress the clutch pedal all the way, the noise stops. Any diagnosis ideas? Thank you!

Have you checked the transaxle gear oil level?
Just offhand, my main suspect would be a transaxle mainshaft bearing problem, although it’s always possible anyway that it could be caused by a fluky throwout bearing or flywheel pilot bearing; all of which require removal of the transaxle.

The reason I asked about gear oil level is that if the transmission is low on oil due to a leak or failure to refill it properly after a gear oil change the mainshaft bearings are the first things to go.