I have an A2ZEV adapter for Super Charger fast DC charging. I've used it once. It works even though support is not official. You kinda need to cheat a bit.
Get the Tesla app on your phone. Setup an account and attach a credit card for billing. Now, here is the cheat: tell it you are a Cadillac Lyric with a NACS adapter. It will now tell you which charger stations are compatible. (NOTE: not all SuperChargers can be used! V2 chargers are Tesla only. V3 and V4 chargers can be used by any compatible car).
When you arrive at a charger the app tells you that you can use, initiate the charge from the app. Do not plug into the car before the app tells you to. But when it does, and you do, charging will start.
I am going to be really pissed if our status is never official however. The built-in NAV system currently will never route us to a SuperCharger because of this, making route planning a bit more tedious than it needs to be. I don't know what is taking so long.