My pixel 4a and 6a both came with usb3 usbc PD cables.
https://old.reddit.com/r/UsbCHardware/comments/14irr99/cable...
Same for the Pixel 6A. Google charging cables are all 2.0.
https://old.reddit.com/r/GooglePixel/comments/xm2fw5/why_doe...
Edit: The above sentence is incorrect, I misread a source. The original Pixel shipped with a USB-A to USB-C cable that supported 3.0 speeds and a USB-C to USB-C cable that supported 2.0 speeds. Since the Pixel 2 they only ship with USB-C to USB-C cables that support 2.0 speeds.
One could speculate that the moment Google knew their phone was a success, they stopped caring about open standards.