Wobbling Pulley

Sorry if this is either in the wrong place or had been covered already. I can't find this topic.

2008 Prius
140,000 miles
Usually just highway driving, 60 miles, 3 days/week.
Bought from deceased family member.
Regular maintenance not done.
Obviously, out of warranty.
I get regular oil changes.

Now for my story;
I was going on vacation and after driving about 75 miles, I started hearing a rattling noise from the engine compartment. I stopped to look at it, but didn't know what I'd be looking for, so I didn't notice anything obvious. But I have Multiple Sclerosis and not much of a car DIY'er.

I was in the middle of nowhere, so I continued driving to the nearest city, about 25 miles. I went easy on it. About a mile from AutoZone, warning lights started coming on. I forget which ones. It also said "Problem". I didn't risk it. I left it at AutoZone, rented a car, and continued on. (A little trick, I joined AAA a few days later. When I got back to the car, I called them, they arrived in 15 minutes and towed it 100 miles to my home. There's a 7 day waiting period for it to be active though.)

When we got it home, I looked more closely. There's a wobbling Pulley. Pic and video included.

Video link;

Like I said, I'm limited in what I can do. But knowing why there's a wobble helps me get the right honest help.

I don't recall hitting anything in the road, or an initial loud noise. Just got louder the longer I drove.

You're the experts. What exactly am I seeing here?

Thank you very much!

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