I think the other thing to consider is that the RX... even an F sport performance... will still be an RX. It probably won't have abrupt, violent acceleration from a stop even if the horsepower is there because it is an RX.As shown in that figure the LS500h AWD has merely 154hp/t. That's comparable power-to-weight ratio to:
None of these cars can do 0-100km/h in 5.4s.
In that well-known Crown video it did 4.7s 0-100km/h. The Crown has 187hp/t, that's comparable to GR86, ES350, LS460. Again none of these can do 0-100 in 4.7s.
I think RX500h performance is understated, but also possibly real. Of course only real world tests will reveal its true performance. It comes down to how quickly the car switches from EV start to ICE on. When you test drive the RX500h it would be very helpful to see whether you can brake torque it like a conventional ICEV.