I have charged at 50 KW EVGo stations a number of times. The Kona charges there with no problems. It looks like they just haven't updated there list with the latest models.
Most EVGo chargers are actually only 40 kw and not the advertised 50kw. 400 Volt x 100 amp = 40kw. The fastest speed I have ever gotten on EVGo was 39kw. On Greenlots or EA 50kw chargers I get 46 kw (EA) and 48 kw (Greenlots). If Greenlots chargers are working, they get excellent speed for a 50kw unit. I wish that there were more Greenlots chargers and that they would maintain them better.. Their $12 per hour is reasonable for a fast 50kw charger.
EVgo is probably the most reliable network. Sometimes, their card readers have issues but you can always use the app.
In DCFC, the throttlling *is* effectively done by the car, through commands to the charger. Appropriate software in the Kona could easily limit both the declared max and working charge rate, by control from the driver, but Hyundai failed to add such configurability for DC and just left it up to some defaults between the BMS and the CCM box. _H*