Just to be clear, you did change the pump? If not that is what needs to happen.
https://www.2carpros.com/articles/how-to-replace-a-power-steering-pump
By raising the RPM you are increasing the pump pressure so we either have a pump issue or a restricted line.
I would flush the system and if it still does it then I would put a new pump and belt on it and retest.
Below is the info on this. Please let us know if you have questions on this. Thanks
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Monday, June 7th, 2021 AT 3:18 PM