There should have been a simple way to label them for usage that was baked into the standard.

There is. USB IF provides an assortment of logos and guidelines for ports and cables to clearly mark data speed (like “10Gbps”), power output (like “100W” or “5A”), whether the port is used for charging (battery icon), etc. But most manufacturers choose not to actually use them for ports.

Cables I’ve seen usually are a bit better about labeling. I have some from Anker and ugreen that say "SS”, “10Gbps”, or “100W”. If they don’t label the power it’s probably 3A and if they don’t label the data speed it’s usually USB 2.0, though I have seen a couple cables that support 3.0 and don’t label it.