Amazon has a whole bunch of those cables/adapters that claim to support 100W/5A charging. Something about being "20 pin" instead of "24 pin" makes even the ones that support high speed links not support thunderbolt, but I'm having a hard time figuring out exactly which pins aren't connected. (It might be the two that are never connected, plus the sideband pins? But that would need awkward wiring, so maybe it's sideband and CC? But that would break more things, I think. So maybe some of it is power pins? But there's 8 of those by default, so why would dropping 4 pins cause it to lose thunderbolt support?)