Sure, if what you mean by standard is it physically fits together but you can’t tell what the heck it’s doing.

Nope. The usb-c on rPi doesn't do usb 2.0.

I think that when plugging an usb-c into an usb-c, we can assume it won't explode, but that's pretty much it. And I wouldn't totally bet on it.

The Pi4 actually does support USB 2.0 over the Type-C port, it just needed a software update to enable it. See https://www.hardill.me.uk/wordpress/2019/11/02/pi4-usb-c-gad...

Had seen too many burned out MBP usb-c ports to believe that nothing will explode...