Take a random port on a random laptop, of any vintage you choose. Pretty much every port you can name is easily identifiable and you can tell what it's capable. HDMI, VGA, USB-A (even with 2.0 vs 3.0), 3.5mm headphone, charging, Ethernet, whatever: any high school student with a passing interest in computers will be able to tell you what you can (and can't) do with it with 95+% accuracy.
USB-C, on the other hand, is all of the above and none of the above at the same time.
Pick a random USB-C port on a random laptop. (We'll leave mobile phones out for now.)
If you're lucky, it's got a little lightning-strike icon, and it's almost certainly Thunderbolt 3 or Thunderbolt 4, and stuff will Just Work. Mostly. To tell if you've got TB3 or TB4, plug in a dock and check if your second 4k monitor works, I guess.
If you're less lucky, it will have a USB Super-Speed logo or something next to it. You might be able to connect a display via adapter if it supports the DisplayPort alt mode, but you won't know till you try.
If you're even less lucky, it will be completely unlabelled. So just plug in stuff and see what works. USB4, perhaps? You might be lucky and have optional TB3 compatibility on it. Possibly one of the various USB 3.0 variations, with their plethora of available speeds. Most likely you'll be able to get at least a USB 2.0 connection to plug in your mouse via a dongle. Might be a weirdly-shaped analog headphone jack, but it's possible (in theory, at least) that the only thing behind it is the same old 5v at a few hundred mA that we've had since the 90s.
And none of these details, as far as I can tell, are documented anywhere.
Fortunately, from what I can tell most laptops nowadays at least support TB3, but I'm sure we'll be plagued by unlabelled mystery ports for quite a while yet.
And yes this is stupidly annoying
There is a problem with the cheap devices that will only charge from USB-A chargers not USB-C. The reason is that they don't spend the cents for USB-C charging chip or the resistors to signal that support legacy USB mode to USB-C charger. The problem isn't the cable or charger, the device is defective.