When I first heard the noise I thought A/C drive clutch - I seem to recall ours made a similar sound many years ago when I think it was failing.

I tend to think that alternators make more of a constant scream/screeching sound rather than a rattle?  I maybe wrong.

But, like Joel I also have come to think that it might be the start of the harmonic balancer out section moving and touching the timing chain cover.   I've seen that happen, although the problem was addressed before the pulley hit the cover.  

I'd also be tempted to check all the nuts on the fan to pump connection and maybe give the fan itself a bit of a "shake" - when its not running of course!😀   Likewise, check the P/S pump bolts for tightness, they don't all need to be tight to hold it in place.

Y’all are great! Thanks for all of the input and suggestions! A/C compressor is new. One of the “fixes” after I got her. I’ll still try the troubleshooting Joel mentioned. I’ll also check out the alternator to see if I feel the noise. That’s about the extent of my skills. lol I’ll keep ya posted. She goes in 1 Nov for diagnosis. 

Whichever culprit it turns out to be, it is NOT an engine noise, so no worries about engine damage, imo. It is one of the accessories...A/C pulley bearing, alternator, water pump, or power steering pump....or harmonic balancer. Should be a fairly easy fix, in any case. 🤠

Looks like your air conditioner pully is not lightened up correctly which will cause bearing damage

It really sounds like a scraping noise to me which could be, as possibly suggested earlier, that the outer ring on the harmonic balancer has moved and is contacting the timing chain cover slightly.