Accessory noise or vacuum leak, give me your best guess

Starting hearing this noise about 8 months ago. Sounds like when crack a hose bib on just enough to get a hydraulic resonance sound going. Replaced belt and no change. Lived with it for a long while then took it to a mechanic and ran a stethoscope everywhere and couldn't pinpoint it. I pulled the belt and felt the power steering pulley had a little front to back play but the pump doesn't make ANY noise when going lock to lock and the sound only happens around 1100-1400 rpm and always the same pitch.
Started the truck with the belt off and noise was gone. Put belt back on and now it squeals like a pig when I start it. I think all my tinkering has made the tensioner give up.
Any ideas would be much appreciated.
Hopefully this youtube link works:
https://youtube.com/shorts/hip1B-YsAy8?feature=share

 

Alternator.

 

Thank you sir. Maybe I'll just go for the trifecta and do alternator/ps/and tensioner. I look forward to only hearing the usual Tundra V8 clatter.

 

Turns out it isn't the alternator. Shop pulled the belt and the noise went away. The did the job and noise is still there. I didn't feel right making them eat the bill so I'm gonna pay them. They have no idea what's causing it.

 

Is it your AC compressor? Never heard a power steering pump make that noise. What else can it be with your serpentine belt off?

 

The first mechanic who looked at it suspected the AC. I disconnected the harness a few weeks ago so it just freewheels and it didn't change but at this point anything is on the table. The shop that just did the alternator may just throw their hands up I guess I can take it to the dealership...or just keep living with it. Thanks for the replies. No matter what I will post the answer if I ever find it.

 

The ac pulley has a bearing and if it fails will make noise. Pulley is always spinning even if clutch is not engaged. Your test does NOT rule out a failing ac pulley bearing

 

You're not wrong but the noise is definitely coming from the passenger side. AC compressor spins smooth with the belt off. I just picked up the truck from the shop after they did the alternator. The noise is different now but not gone and that actually worries me more.

 

Replacement alternator was crap and causing the noise. Now doing the job myself.