Sounds like the power steering pump is failing. More then likely the pump is locking up and when you turn the wheel and the pressure goes up it actually slows the belt down and the alternator slows down and the engine RPM drops.
What I would suggest is remove the belt and then drive the vehicle. Clearly you won't have any power steering but just back it up in a parking lot or other safe place just to test it. If it still does it then it is not the pump.
However, I suspect it won't have the issue at which point I would replace the pump.
Below is the process from the manual that will help with this as well.
Let us know what happens. Thanks
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Monday, April 5th, 2021 AT 5:22 PM