Kitchenaid 600 Pro Mixer high pitched noise

There's no "unbiased" way for me to say this. I own three KitchenAid mixers and have used several others. Only one of these makes a loud, screaming noise, and it hasn't improved or calmed down or settled in the 5 years I've owned it. The one that makes the terrible noises was made in Mexico and even looks slightly different in some small construction details than the others which were made in the USA. I bought the "problem child" at a big box store for a slightly lower price than I might have found it at a home store, but it was the color I'd been looking for so I went for it. Not my best choice in the world.

There's a TikToker, @mr..mixer, who might be able to help you troubleshoot that annoying sound. He even has a YouTube channel (search "Mr. Mixer Kitchenaid). I had him do a total maintenance and regrease (on the gears) on my Kitchen (16 yo Artisan series) this summer. My KA is much quieter and will actual stir at a low speed now (there's a way to adjust the speed on your mixer, did you know that?). He even changed the somewhat melted cord too.

Anyhoo, having watched many of his TT videos, it might be a problem with the gears grinding and possibly, the drive shaft is not centered.

Even Mr. Mixer has said that KA mixers today are not built as well as the much older models. Having seen all things that have been changed over the years, I'm inclined to believe him. Disclaimer: I do not know this man nor do I have any stake in his business.

Kitchen Aid stand mixers do sound kind of like aircraft taking off, due to the motor design. But it shouldn't sound like a high pitch squeal by any means. Usually that means your gears need grease. If anyone you know owns one, or there is a kind kitchen supply shop near you that wouldn't mind doing a demo- you could hear and compare the sounds. I've had mine going on 20 years now, and the only thing it has needed is a new cord attached.

Machines making screeching sounds certainly don’t sound normal or good.
A quick look at google and you tube only found reports of a balance/levelling problem being common.
What I would want to find out - if it were my machine - is whether the sounds are temporary/the result of usage/fixable or permanent/part of this machine/not fixable? And maybe unsafe to use.
What news or opinions from customer service?

My Kitchenaid is pretty loud/whiny! I do think they tend to be. Any way you could call their customer care and turn it on for them to hear? My guess is that you can't be the first person who has reached out to them about this! Might be worth a try.