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Apple to Limit iPhone 15 USB-C Cables to USB 2.0 Speeds: Report
(www.extremetech.com)
This is a most excellent place for technology news and articles.
I highly doubt the limitation is going to be at the cable. They are generally known for their high quality production capabilities, meaning they would have to actively make the cable worse (and likely cost more while doing so.)
They are likely going to simply limit the controller to 2.0 speeds.