Metallic squealing noise from engine > 2k RPM

Have you tried the a.c. compressor? Maybe the internal crankshaft of the compressor is failing causing the harshness. Mine typically only makes the metallic whining noise under load, when the a.c. fan is on (figured this out and seems to be a major contributor to the grinding metallic noise, maybe electical related where a signal isn't strong enough or grounded. Idk) was also thinking power steering, but it is on the opposite side, but maybe this being a tiny bit loose and causing misalignment would cause a metallic squeal from the belt being warped and under load just adds to the tension so one pulley scrapes on the front of the engine or maybe the a.c. clutch or bearing is shot. Just trying to pick this convo back up. I need all new cats again. Have this noise as well as the chatter from the tensioner arms in the timing chain case. Seems aggravating. Also changed the radiator fan clutch, idler pulley, tensioner and bracket, only other components on the upper left (driver side) of the engine are the internal water pump, maybe the blades wore down internally, or the a.c. compressor and clutch, which I was told to also replace the a.c. condesor if the compressor goes bad in case there were any metal shards that could cause more issues. Thinking it could just be the bearing and a.c. compressor clutch and hopefully not the entire compressor unit. Hope to rectify this and get some suspension components and the new catalytic components and drive it for another decade

It was loud before, now it is quiet when the fan is off, but if you turn the truck off when the fan is on, it usually starts with it on. If you let it cool down and then shut off, it sometimes stays on, but always idles quietly after a little warm up. I hope my issues are solved by revamping and sealing my exhaust with new components and gaskets. Might also get exhaust manifolds if they look bad. New hoses and clean my maf sensor and see if I can get it idling and running smoother. Feel as though I might have a bad bearing or shaft somewhere. Or one of my pulleys is loose on one side causing grinding on the opposite pulley which could have damaged it that way. Not 100 percent. My power steering pump had a bit of play, but it's on opposite side of the drive belt from the source of the grind. Thinking a.c. compressor or internal water pump blades. Or misalignment.