My Graphie make this ODD sound back around 2014. I simply could not tell where it was coming from, but I was sure it was not the water pump (which it often is).

I replaced the belt tensioner assembly and idler pulley. FIXED. Took some 45 minutes and cost me something like $110 in parts. 45 easy minutes, and I'm no mechanic.

Look at it this way, you usual noisemakers are: Alternator, idler (common failure item), water pump (always fail between 90d and 150k miles) , power steering pump (rare failure item), belt tensioner (somewhat common failure item), A/C pump/clutch (rarely makes noise). Idlers go bad, it seems, a LOT and only cost $17, belt tensioners are actually cheaper these days and, again, are EASY to change.