I never said the charger could handle 1000kW. I said "unless four cars show up at exactly the same moment at very low states of charge" you won't be restricted.
Which clearly indicates that 1000kW is not possible.
The 250kW charge rate drops rather quickly. At best, you start at 5% and have the 250kW rate for 15% of the charge. Let's see - 15% of 75kWh = 11.25 kW. At 250 kW, you charge at max rate for 2.7 minutes. Then it's 10 minutes to add an additional 40%/30kWh to get to 60% where you are drawing 110kW. See how quickly it drops off? The last 30% of the charge (22.5kWh) takes 18 minutes, as your charge rate evenly declines to 40kW
Unless Model 3 LR show up at 5% SOC faster than every 8 minutes, the charger can handle it.
You're more likely to be limited by a V3 charger that isn't working properly, than an actual charging load.